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Considering that high-purity fresh water is employed in the green production of hydrogen via commercial water electrolyzers and that over 80% of the global population faces significant water safety risks, it is essential to explore alternative water sources. One such alternative is the use of produced water from oil extraction processes. Hence, the main objective of this study is to evaluate the effect of the oil content of oilfield production water on the production of green hydrogen by electrolysis in the presence of carbon quantum dots (CQDs). For this purpose, various electrochemical techniques, such as linear sweep voltammetry (LSV), cyclic voltammetry (CV), and potentiometry, were used to identify the effect of crude oil during hydrogen production. Thermogravimetric analysis (TGA), mass spectrometry (MS), and Fourier-transform infrared spectroscopy (FTIR) were employed to discern the adsorption of crude oil onto the electrodes, quantify the gas fractions generated during the process and identify the functional groups present after the procedure, respectively. Also, optical microscopy was employed to follow the droplet size in the emulsion. The results show that using CQDs affects the Faradaic efficiency, which increases from 77% to 83% with the incorporation of CQDs. In the presence of CQDs, the effects generated by the presence of the oil are inhibited at low oil concentrations. On the contrary, hydrogen production increases by 10.0% (0.1 mL/min) with a faradaic efficiency of 83% and a half-cell efficiency of 41%, compared to the record obtained with the maximum concentration of emulsified crude oil (400 mg/L). The mean size of the initial emulsion droplets was 3.4 μm. At the end of the test, there was evidence of complete breakage of the emulsion due to the effect of the applied electric field. No evidence of adsorption of crude oil on graphite electrodes during electrolysis is observed based on the tests. It has been shown that green hydrogen production from crude oil production water is feasible due to the proposed disruptive electrolytes in the produced water, which inhibit the effect of oil content in the O/W emulsion. This allows the implementation of a new green energy production initiative aligned with the global goal of achieving net zero emissions (NZE) by 2050. The current investigation presents a prospective alternative for harnessing the 18 kW electrical energy potential employed within emulsion-breaking processes within a Colombian field for treatment of around 1000 bpd. This alternative offers a theoretical potential for hydrogen production, approximating 7.36 kW, thus representing a promising opportunity for practical field deployment. • CQDs in electrolysis enhance green hydrogen production efficiency from oilfield-produced water due to their conductive properties. • CQDs significantly increases Faradaic efficiency, inhibiting crude oil's negative effects on hydrogen generation. • Optimized electrolysis with CQDs result in 10% higher hydrogen production at high concentrations of emulsified crude oil. • CQDs mitigate crude oil's negative effects on the system, such as reduced conductivity and electrode degradation. • Gas analysis demonstrates the feasibility of converting oilfield production water into a valuable resource for green energy. [ABSTRACT FROM AUTHOR]

Hydrogen (H 2) is widely acknowledged as a promising, sustainable, and environmentally friendly energy carrier, offering numerous environmental benefits over conventional fossil fuels. However, the advancement of this technology is severely hindered by the scarcity of effective and robust catalysts for hydrogen evolution (HER) and oxygen evolution (OER) reactions activity. This study marks the inaugural fabrication of a hybrid tri-metallic electrocatalyst, termed MnCoCu–P, through hydrothermal synthesis. Subsequently, the catalyst undergoes atmospheric O 2 plasma surface activation, aiming to amplify the efficiency of water splitting. The novel atmospheric O 2 plasma-activated MnCoCu–P electrode outperforms the reported classic metal phosphides, and it outperformed the compared commercial Pt/C and RuO 2 benchmark catalysts with outstanding performances of 0.488 and 1.20 V towards HER and OER at 1000 mA/cm2, respectively. Additionally, the MnCoCu–P (5 min) catalyst Faradic efficiency was calculated under alkaline conditions in 1.0 M KOH, and both the produced gas H 2 and O 2 match the theoretical and experimental calculated values well, indicating a high efficiency of almost 100%. In the 2-E system, MnCoCu–P (5 min)‖MnCoCu–P (5 min) demonstrated remarkable performance by attaining a current density of 1000 mA/cm2 at low total cell voltages of 1.93 V and outperforming the benchmark Pt/C‖RuO 2 electrode system. On the other hand, the MnCoCu–P electrode possesses excellent activity under industrial conditions at 6.0 M @ 60 °C exhibited 1.89 V at 1000 mA/cm2 and performs well in natural water systems. Moreover, the 5 min O 2 plasma-treated MnCoCu–P‖MnCoCu–P electrodes showed improved activity in all the pH solutions which makes it one of the potential candidates for commercial application in the future. [Display omitted] • Trimetallic MnCoCu–P catalyst was successfully fabricated via one-step hydrothermal approach. • The 5 min O 2 plasma-treated MnCoCu–P catalyst showed excellent electrocatalytic activity. • MnCoCu–P (5 min)‖MnCoCu–P (5 min) showed enhanced activity under industrial conditions. • MnCoCu–P (5 min) electrode exhibits comparable performance in universal pH and natural water. [ABSTRACT FROM AUTHOR]

Clean (green) hydrogen can be generated via water electrolysis using photovoltaic, wind, hydropower, or decarbonized grid electricity. However, there is a lack of environmental and economic trade-offs for alternative production in the low-carbon transition. This study presents an assessment framework for analyzing the environmental-economic tradeoff indicators of replacing traditional hydrogen production pathways with green alternatives, with an illustrative example drawn from the baseline scenario in which green hydrogen replaces coal for hydrogen production in China. The production system for green hydrogen in China will be competitive with traditional methods by 2030, leading to a significant transition. The priority order of the renewable energy technology portfolio for hydrogen production via water electrolysis is PV-ALK > WP-ALK > WP-PEM > PV-PEM. Regions with high trade-off indicators have the comprehensive benefit of promoting green hydrogen substitution, and Inner Mongolia, Heilongjiang, Jilin, Liaoning, Hebei, and Xinjiang have lower decarbonization costs and can obtain better abatement benefits. The system of trade-off indicators from the perspective of emission reduction can guide the selection of green hydrogen production technologies and project planning and will be further improved. • Analyzing GHG of green hydrogen from cradle to gate, considering hydrogen leakage. • Comparing dynamic LCOH for various business models and technology combinations. • Evaluating environmental-economic trade-offs for the expansion of green hydrogen. • Discussing the benefits of decarbonization through the substitution of green hydrogen. • Proposing an environmental-economic tradeoff index for green hydrogen replacement. [ABSTRACT FROM AUTHOR]

To achieve long-term and efficient photobiological hydrogen production by green algal aggregates remains a challenge. Herein, we demonstrated that mixotrophic cultivation of green algal aggregates can greatly increase the hydrogen production of Chlorella pyrenoidosa by 37 times, and the period of the hydrogen production was up to 21 days with a hydrogen yield of 14.97 mmol L−1. We found that glucose enabled the green algal culture flocculated by cationic etherified starch anaerobic overall, while the algal cells remained highly active. Therefore, long-term effective hydrogen production by green algae was realized. The simplicity and low cost of the method, which requires only cationic etherified starch and glucose, gives it a good potential for scale-up applications and a positive impact on the energy and environment fields. [Display omitted] • A new strategy of mixotrophic cultivation increased the H 2 production by 37 times. • H 2 production was prolonged to 21 days by supplementation with 50 mM glucose. • Large green algal aggregates up to 1000 μm were formed. • Algal aggregates were wholly anaerobic while maintaining high cellular activity. [ABSTRACT FROM AUTHOR]

The discovery of triboelectric nano-generators (TENGs) has resulted in the invention and development of self-powered electronics and devices. TENGs offer numerous benefits including their portability, affordability, and sustainable micro-scale energy harvesting in the realm of self-powered sensors and portable devices. TENGs have the capability to function as an autonomous power source. Integration of TENG with electrochemical processes can facilitate self-powered electrochemistry such as water splitting (or electrolysis) for H 2 production, thereby eliminating the requirement for an external power supply. This review primarily centers on the operation and the recent advancements of TENGs in self-powered water-splitting for clean and environment-friendly H 2 production utilizing renewable energy sources including wind, wave, and low-scale mechanical energy. The concept of conducting water-splitting without reliance on an external power source holds the potential for significant use in the field of clean and green H 2 production with cost advantages, sustainability, and other environmental benefits. [Display omitted] • Analysis of principle and working of triboelectric nano-generators (TENGs). • Utilization of TENGs in self-powered water splitting devices. • Review on the recent advances in conversion of wind, wave and low-scale mechanical energy by TENG to clean and green H 2 production. • Summarized benefits, challenges and perspective of TENG based self-powered electrolysis. [ABSTRACT FROM AUTHOR]

Green hydrogen has an audible echo in the clean energy field. In this piece of work, pure and Mo-doped CuO thin films were deposited at different substrate temperatures on the Indium Tin Oxide (ITO) by the DC/RF sputtering technique. The prepared samples were utilized to generate hydrogen gas within the photoelectrochemical water-splitting mechanism. Crystallographic planes (−111), and (200) were the preferred orientations for pure and Mo-doped CuO thin films. Moreover, the average crystallite size was doubled by Mo doping reaching 25.8 nm. FE-SEM microscopic image exhibits that the pure and Mo–CuO thin films have a regular distribution with a small size. The optical band gap has rosed by doping from 1.8 eV to 2.05 eV. Then, it increased to 2.3 eV and 2.4 eV at temperatures of 100 °C and 200 °C respectively. Pure and Mo–CuO thin films were applied as photocathodes for hydrogen generation with water water-splitting technique. The photoelectrochemical application revealed a photocurrent density of ∼2.25 mA/cm2 for Mo-doped CuO photoelectrode at room temperature. This optimum photoelectrode was studied for stability and electrochemical impedance. In addition, the incident photon to current efficiency (IPCE%) was 4.47 % at 500 nm. The applied bias photon to current conversion efficiency (ABPE%) was 4.25 % at −0.38V. As a result of the above, pure and Mo-doped CuO photoelectrodes are low-cost thin films and have a high-efficiency performance for green hydrogen generation industrially. • Mo-doped CuO thin films were carefully sputtered on an ITO substrate at different temperatures. • Effect of doping and temperature on structural and optical properties of CuO thin films has been studied. • The efficiency of Mo-doped CuO photoelectrode at room temperature outperforms the rest. • Photocurrent density ∼2.25 mA/cm2 and (ABPE%) 4.25 % at −0.38V were revealed. • Mo–CuO photoelectrodes have a high level performance for green hydrogen generation. [ABSTRACT FROM AUTHOR]

Green H 2 (GH) has emerged as a highly promising medium for the transportation of eco-friendly energy. The utilization of H 2 as the primary operational medium in H 2 -based energy storage systems and fuel cells has facilitated the integration of these systems with various other renewable energy sources, rendering such integration highly viable. This review presents an overview of the current advancements in the field of GH production techniques using water electrolyzers powered by renewable energy sources. The present paper starts with a concise overview of several production techniques and a detailed analysis of various types of water electrolyzer. It also offers a thorough examination of H 2 production methods utilizing solar, wind, and hybrid systems. An economic evaluation of GH production was analyzed by comparing the costs associated with different renewable sources. This study focuses on investigating the challenges and advantages of GH and the implementation of large-scale commercial operations. The proton exchange membrane water electrolyzer (PEMWE) technologies boast higher current densities (1-2Acm−2) than alkaline water electrolyzer (AWE); the PEMWE technologies also produce a higher purity of H 2 up to 99.9999 %. The wind energy-associated PEM LCOH ranges from 5.3 to 9.29 $/kg. AWE had levelized cost of H 2 (LCOH) of 7.49–7.59 $/kg. Other studies show that SOE-based LCOH ranges from 6 to 9.34 $/kg and should drop to 1.9 $/kg by 2050. The cost of GH was found to be significantly influenced by the rated wind speed compared to other wind turbine parameters, and it ranged from $1.7/kg to $40.00/kg. [Display omitted] • GH could help reduce global warming and transition to a more sustainable energy system. • Discussion on grand challenges, prospects, and key recommendations to the commercialization of water electrolysis systems. • The lack of global hydrogen standards hinders the growth of the global hydrogen market. [ABSTRACT FROM AUTHOR]

Unwanted consequences associated with entropy waves, such as increased NOx emission levels, combustion instability, and generated noise, have long been recognized in the field. Indirect noise or acceleration of entropy oscillations acts as a source of noise, that contributes to the instability of the combustion chamber. To gain a deeper understanding of these occurrences, an investigation was conducted to computationally explore the entropy noise in a lean-premixed green H 2 /ethylene burner. This research used the flamelet model and large eddy simulation methods and provided valuable insights into the behavior of entropy waves and their influence on combustion dynamics. The research specifically focused on investigating the impacts of diverse thermal and fluidic conditions on entropy noise in both circulation and adiabatic combustion chambers in terms of temperature. Factors such as inlet turbulence strength, inlet velocity, stoichiometric ratio, and preheating of the unburned mixture were meticulously scrutinized. The results of the research show that there are surprising correlations between the examined variables and the acoustic response of the system. It was noticed that the increase in inlet velocity, equivalence ratio, and temperature resulted in an escalation in the auditory response. These results indicate that higher inlet velocity, greater equivalence ratio, and increased temperature circumstances encourage the creation and propagation of entropy noise. On the other hand, the investigation showed that the intensity of the amplifier turbulence had an adverse influence on the conduction of entropy oscillations and consequently diminished the auditory response. This indicates that excessive turbulence intensity can disrupt the propagation of entropy waves and diminish their capability to generate a substantial acoustic response. • A mixture of hydrogen-ethylene fuel was assessed in terms of noise generation. • The generated acoustic noises are influenced by the variations in wave entropy dissipation. • Increasing the inlet excitation amplitude intensified the further entropy wave annihilation. • Preheating the unburned mixture improved entropy wave stability. • Realistic walls and inlet flow conditions resulted in a lower level of noise generated. [ABSTRACT FROM AUTHOR]

In the climate changing context, hydrogen is leading the energy transition path. The present work focuses on the green hydrogen production exploiting salinity gradients via Reverse Electrodialysis (RED), in short-circuit condition (RED SC), and Assisted RED (ARED), studied for the first time in hydrogen production as an improvement of the low current densities generated by RED. An extensive experimental campaign was carried out by feeding a RED stack with different salinity gradients and testing short-circuit-RED and Assisted RED operative conditions. Hydrogen was produced successfully with ∼100 % Faradic Efficiency (FE) and productivity up to 1.7 mol h−1 m−2. Also, the technology was compared with similar technologies and with the most established state-of-the-art electrolysers to identify advantages and disadvantages of the proposed route. Finally, a preliminary economic analysis was carried out and a minimum Levelized Cost of Hydrogen (LCOH) of 3.2 € kg−1 H2 was found, thus leaving room for further studies. [Display omitted] • Green hydrogen production from salinity gradient by Reverse Electrodialysis • Production boosting via Assisted Reverse Electrodialysis (A)RED for the first time • Investigation of hydrogen production under different operating conditions • Comparison of the proposed electrolyser with the state-of-the-art • Preliminary economic assessment with calculation of the Levelized Cost of Hydrogen [ABSTRACT FROM AUTHOR]

Protonic ceramic electrolysis cells (PCECs) have attracted significant attention as a promising technology for green hydrogen production and conversion. However, traditional PCECs oxygen electrodes exhibit poor electrochemical performance because of their limited hydration ability and lack of intrinsic protonic conductivity. In this study, a W-doped perovskite oxide, Sr 2 Fe 1.5 Mo 0.4 W 0.1 O 6-δ (SFMW), with a strong hydration capacity and an accelerated proton mobility, was designed to serve as the oxygen electrode in PCECs. The results indicate that W doping enhances the concentration of oxygen vacancies in Sr 2 Fe 1.5 Mo 0.5 O 6-δ (SFM) and facilitates the adsorption of H 2 O onto the oxygen electrode, thereby significantly accelerating proton mobility. The bulk diffusion coefficient of protons (D H) in SFMW, estimated through electrical conductivity relaxation measurement, can reach up to 2.86 × 10−5 cm∙s−1 at 750 °C, which is significantly higher than that of SFM (7.96 × 10−6 cm∙s−1). Consequently, SFMW exhibited impressive electrochemical performance, as evidenced by its lower polarization resistance (0.072 Ω⋅cm2, 700 °C in air) and higher current density (945 mA/cm2 with a voltage of 1.3 V at 650 °C) in PCECs. These results suggest that accelerating bulk proton transfer by W doping is highly feasible and holds great potential for the development of oxygen electrodes for high-activity PCECs. [ABSTRACT FROM AUTHOR]

The rapid development of the transportation sector requires consideration of fossil fuel consumption and its negative effects. For this reason, electric vehicles have started to be an alternative to conventional ones that use fossil fuels. As a transportation fuel, hydrogen can be considered as a suitable alternative to fossil fuels. The durations for hydrogen refueling and fossil fuel refueling in conventional vehicles are close to each other. To promote the use of fuel cell vehicles, it is imperative to build the necessary facilities, including hydrogen fuel stations, that will support this need in the near future. In this study, the refueling of the hydrogen tank is simulated for the use of a fuel cell electric vehicle in real usage conditions and it takes 280 s to supply 4.34 kg of hydrogen to the tank of the vehicle, which is driven with a range of 650 km. The fuel economy of the vehicle is compared with conventional vehicles and was found to be 11.0 ¢/km and 10.2 ¢/km, respectively. Renewable supported production technologies are taken as a reference in hydrogen pricing, and these costs are even lower in hydrocarbon-based production. Depending on the source of the hydrogen, the emission intensity of the vehicle can be reduced to 4.7 gCO 2 /km with green hydrogen technologies, while it can be up to 166.8 gCO 2 /km in case of intensive fossil resource use. This study shows that a fuel cell vehicle can compete with traditional ones in terms of range, refueling time and fuel economy and is more environmentally friendly. • An FCEV is simulated in the designed driving cycle based on real-world data. • Vehicle fuel consumption is 6.67 gH 2 /km or its gasoline equivalent is 2.51 L/100 km. • The vehicle can travel 650.3 km with 4.34 kg of hydrogen. • Refueling time for a 650 km trip takes 280 s. • The emission value of the vehicle is between 4.7 and 166.8 gCO 2 /km. [ABSTRACT FROM AUTHOR]

As the most abundant element in the universe, hydrogen presents considerable potential as an energy carrier for the decarbonization of diverse economic sectors. The essential role played by Polymer Electrolyte Membrane (PEM) water electrolyzers (WEs) in enabling the production of green hydrogen through water electrolysis underscores their significance, owing to their rapid dynamic response and high energy efficiency. This study focuses on utilizing photovoltaic (PV) generated electricity for hydrogen production via Proton Exchange Membrane Water Electrolysis (PEMWE). During the electrolysis process, especially when generating hydrogen, there is a requirement for low voltage and high current levels. To regulate the output voltage from PVs, a buck converter has been employed. Nevertheless, optimizing the performance, efficiency, and operational lifespan of PEM WEs necessitates the application of robust control algorithms. The control system incorporates the Perturb and Observe (P&O) and Fuzzy Logic (FL) algorithms, with a comparative analysis of their respective outcomes. Simulation results indicate that the FL Controller exhibits superior efficiency and enhanced performance when compared to the conventional P&O method. • Solar energy is used to obtain clean energy. • Hydrogen is generated with electrolysis process. • DC-DC buck converter is used to reduce voltage and increase current for electrolysis. • The Perturb and Observe (P&O) and Fuzzy Logic (FL) algorithms are modelled to control. [ABSTRACT FROM AUTHOR]

The presented paper focuses on renewable energy-assisted electricity, hydrogen, and cold energy production. Solar energy is used as the energy source in the study. The organic Rankine cycle (ORC) is used for electricity generation, a proton exchange membrane electrolyzer (PEMe) for hydrogen production, and an ejector refrigeration system for cold energy production. The study is based on the exergy concept and examines thermo-economic and thermo-environmental analyses. The exergy efficiency of each equipment in the system is calculated from a holistic perspective. Considering the energy consumption values of the equipment in the whole system, the cost required for hydrogen production is calculated as 1.086 $/kg. Additionally, the exergy efficiency of the whole system is found to be 2.082 %. • Thermodynamic analysis of the solar-based hydrogen production system. • The exergy efficiency of the whole system is found as 2.082 %. • The cost of green hydrogen production is found as 1086 $/kg. [ABSTRACT FROM AUTHOR]

Biorenewable hydrogen is requisite to replace non-renewable hydrogen. Decarbonization is assured. Hydrogen demand is severely rising due to mitigating climate change and reducing fossil fuel dependency. Green Hydrogen from agro waste proposition makes bio-circular economy upcycling. The main objective of this study is to reinforce the hope of renewable, sustainable H 2 production from agro-waste. Initially, this paper shows the demand for green hydrogen, the sustainable availability of agro waste, and their capability to produce H 2. Insights into the gasification of agro waste about cellulose, hemicellulose, and lignin with conventional gasification. The effect of catalyst and supercritical gasification and their challenges is discussed. Most uniquely, other reviews highlight various aspirations behind agro-waste gasification to attain a strong business model, such as co-production, co-gasification, and CO 2 reforming with H2 yield. This review exhibits some main insight into various aspects of agro-waste gasification. H 2 from agrowaste gasification has high energy content (122 kJ/g) and high energy conversion efficiency in the range of 55–58 %, in addition to gaining the economic penalties of 2.2–2.5 net points for decarbonization. Agro waste is composed of lignocellulosic material that is relatively richer in hydrogen than fossil fuel resources. In SCWG, water is one of the natural solvents, which means feedstock effectively dissolves with water solvents. Intermittent density, low viscosity, and surface tension are nearly zero values due to SCW having no specific phase boundary, which enhances the gasification and substantially reduces tar formation during SCWG. Catalyst utilization enhances H 2 production. The present study comprehensively exhibits the role of catalyst and their supporter and promoter. Ni-based catalysts are mostly suggested for H2 production but fall into reusability issues. The main reason behind this is that Ni is inefficient in removing HCl, H 2 S, and total trace elements during gasification. Recently, low-cost and waste-to-wealth transformation aspects of biochar-based catalysts have gained attention. Renewable-assisted gasification significantly improves the energy and exergy of the system and suppresses the important concern of energy consumption during gasification. Renewable assisted and various aspiration incorporation into gasification is solidly recommended for future implementation based on energy, economic, and environmental benefits from them. Plastic and biomass are richer in hydrocarbon and oxygen, respectively; this synergistic effect has the potential to enhance the H 2 yield. From this study, PP plastic is mostly preferred for co-gasification with biomass. Compared to 100 wt% of biomass, the introduction of plastic slightly increased the coke formation, but the H 2 yield was improved. When the plastic mixture of 10 wt% increases coke deposition, however, significant coke deposition is not reported when 20 wt% of plastic concentration is not reported. Carbon capture via CO 2 inert gas supply enhances the H 2 yield, provides a route to carbon trade, and substantially contributes to GHG pollution mitigation. Agro-waste gasification is produced by a product that has the potential to be used in a wide range of applications due to its unique properties, such as large specific surface area, porosity, functional groups, high reliability, and minimum cost. Hopefully, this review will be an optic to the most appropriate green hydrogen production path for sustainable clean energy production and effective agro-waste management. • This review acts as an optic to the most appropriate green hydrogen production path. • Hydrogen separation, purification, and storage need more care. • Carbon dioxide reformation aids a carbon trading system and reduces environmental effect. • These research provide direction for energy nexuses that may be derived from agricultural waste. [ABSTRACT FROM AUTHOR]

This study examines the potential for hydrogen to undertake a leading role in the transition to sustainable energy in Türkiye. Türkiye, with its well-established energy infrastructure and increasing focus on renewable energy, has the potential to undertake a significant part in the worldwide hydrogen market. The research uses a multi-level perspective to analyse the interactions between different region connected with Türkiye, and the processes and strategies within the national energy system. The findings suggest that hydrogen production and transport in Türkiye has the potential to significantly contribute to the decarbonization of the industry and flexibility services in Asia, Europe and Africa. However, the ongoing advancement in the field of hydrogen in Türkiye is at a critical juncture where coordinated efforts are necessary to fully realize its potential. Türkiye recently announced the Hydrogen Technologies Strategy and Roadmap. Under the new Hydrogen Technologies Strategy and Roadmap, Türkiye plans to significantly increase the production of hydrogen. Türkiye plans to significantly increase its installed electrolyser capacity to support the production of hydrogen. Specifically, the plan aims to increase the installed capacity to 2 GW by 2030, 5 GW by 2035, and 70 GW by 2050. Turkey's strategic investments and policy adjustments could propel its green hydrogen production to 3.4 million tons yearly by 2050. With an anticipated domestic demand for hydrogen at 1.9 million tons annually, Turkey could potentially export between 1.5 and 1.9 million tons yearly by 2050. Türkiye boasts an extensive network of transmission and distribution pipelines for natural gas, totalling 10,000 km, including those with large diameters. The existing pipelines could transport hydrogen in its pure form or blended with natural gas. The natural gas pipeline capacity in Turkey stands at 32 billion cubic meters. This infrastructure enables the transportation of an estimated 575 million tons of hydrogen yearly to neighboring countries by employing a mix of 20 % hydrogen and natural gas. With an extensive network of natural gas transmission and distribution pipelines, Turkey positions itself as an integral part of the interconnected hydrogen energy infrastructure, linking the nation with Europe and neighboring regions. The results of this study present new approaches into the dynamics of the energy system and contribute to ongoing discussions about transition routes and consider the current status of hydrogen in Türkiye, the country's renewable energy potential, the policy and regulatory framework, and the infrastructure and market conditions necessary in order to foster the growth of a hydrogen hub. • Turkey holds substantial potential in the global hydrogen market. • Turkey's gas infrastructure supports hydrogen integration. • Turkey, Latin America, Middle East shifting from hydrogen importers to exporters. • Hydrogen to play a key role in Turkey's energy shift. [ABSTRACT FROM AUTHOR]

The current study examines a novel multigeneration plant that uses geothermal energy to produce clean and sustainable products. The process includes a re-compression supercritical Brayton power plant (re-sBC), an ejector cooling unit (EJCS), a humidifier dehumidifier desalination (HDH) unit, a Proton-Exchange Membrane (PEM) process, and a hot water preparation unit. The designed plant is able to generate hot water, cooling, power, hydrogen, and freshwater using the geothermal source. In the current paper, the thermodynamic analysis, CO 2 emission assessment, and exergoenvironmental index evaluation are executed to determine the system efficiency and the association between the system and the environment. A thorough parametric examination is fulfilled, to show how the system indicators impact efficiency and generated products. According to analysis data, the proposed multigeneration plant is able to generate 1278 kW of heating load, 229.6 kW of refrigeration capacity, and 109.5 kW of net power rate. Additionally, the capacity of the freshwater is 0.1188 kgs − 1 and the hydrogen is 0.001317 kgs − 1 . This developed system emits a total of 117 tonnes of CO 2 emissions per year for these useful outputs. In conclusion, the energetic and exergetic performance of the suggested MG plant are 14.09 % and 23.35 %, respectively. • A sustainable geothermal energy-based MG is proposed. • The thermodynamic, emission, and environmental analysis is conducted. • Design and evaluation of the Green hydrogen production and storage. • Re-compressed sBC integrated into geothermal driven MG plant. • Total energy and exergy efficiency is computed as 14.09 % and 23.35 %, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] The pursuit of efficient and sustainable hydrogen production through water splitting has led to intensive research in the field of electrocatalysis. However, the impediment posed by sluggish reaction kinetics has served as a significant barrier. This challenge has inspired the development of electrocatalysts characterized by high activity, abundance in earth's resources, and long-term stability. In addressing this obstacle, it is imperative to meticulously fine-tune the structure, morphology, and electronic state of electrocatalysts. By systematically manipulating these key parameters, the full potential of electrocatalysts can unleash, enhancing their catalytic activity and overall performance. Hence in this study, a novel heterostructure is designed, showcasing core–shell architectures achieved by covering W 2 N-WC nanowire arrays with tri-metallic Nickel-Cobalt-Iron layered triple hydroxide nanosheets on carbon felt support (NiCoFe-LTH/W 2 N-WC/CF). By integrating the different virtue such as binder free electrode design, synergistic effect between different components, core–shell structural advantages, high exposed active sites, high electrical conductivity and heterostructure design, NiCoFe-LTH/W 2 N-WC/CF demonstrates striking catalytic performances under alkaline conditions. The substantiation of all the mentioned advantages has been validated through electrochemical data in this study. According to these results NiCoFe-LTH/W 2 N-WC/CF achieves a current density of 10 mA cm−2 needs overpotential values of 101 mV for HER and 206 mV for OER, respectively. Moreover, as a bi-functional electrocatalyst for overall water splitting, a two-electrode device needs a voltage of 1.543 V and 1.569 V to reach a current density of 10 mA cm−2 for alkaline water and alkaline seawater electrolysis, respectively. Briefly, this research with attempting to combination of different factors try to present a promising stride towards advancing bi-functional catalytic activity with tailored architectures for practical green hydrogen production via electrochemical water splitting process. [ABSTRACT FROM AUTHOR]

For the transformation of energy conversion and photocatalytic decomposition, photocatalyst-based artificial photosynthesis for solar-to green fuels and environmental treatment has aroused great attention. Herein, a novel ternary heterojunction based on constructing an interaction between 2D-graphitic carbon nitride (CN), 3D-strontium titanate (STO) and Pt nanoparticles (NPs) (2D/3D CN/STO@Pt) is designed for the first time to greatly promote photocatalytic water cracking hydrogen (H 2) evolution in an alkalescent environment, such as triethanolamine (TEO) as well as integrating with Rhodamin B (RhB) decomposition. Under optimized conditions, the H 2 productivity over 3D/2D CN/STO@Pt-3 heterostructures (10,005 μmol h−1 g−1) with an apparent quantum yield of H 2 production approaching 47.5% is found to be ∼29.7, 8.5, 1.1, and 1.5-fold as much as that in the CN, CN/STO, CN/STO@Pt-1, and CN/STO@Pt-5 heterojunctions, respectively. An up to 2.5-fold enhancement in the photocatalytic RhB decomposition rate, obtaining 90% within 60 min under visible-light-driven is observed for 3D/2D CN/STO@Pt-3 heterostructures, surpassing that of other samples. The CN/STO@Pt-3 sample shows the highest degradation rate of 3.5 min−1, which is 1.8, 2.8, 4.27 and 4.9 -time higher than that of the CN/STO@Pt-1, CN/STO@Pt-5, CN, and STO samples, respectively. The improved photocatalytic behavior of the heterogeneous structures could be ascribed to i) the type II-heterojunction between 2D CN and 3D STO; and ii) the creation of the Schottky contacts between semiconductors and Pt NPs. The configuration of the type-II heterojunction formed by the two semiconductors of 2D g-C 3 N 4 and 3D STO contributes to improved light absorption ability, and rapid separation and transfer of photoinduced charges. At the same time, the close junction of Pt establishes the Schottky barrier to facilitate efficient electron transfer in the ternary nanostructures, impeding the quick recombination of photoexcited charge carriers, and offering abundant reactive sites, contributing multiple electron pathways for the photoreaction strategy. Increased photocurrent density from the LSV measurement and a declined in PL intensity confirmed the enhanced interfacial charge separation in the tertiary photocatalyst. Furthermore, the CN/STO@Pt-3 ternary heterostructure presents outstanding photocatalytic performance after five cycles, indicating good stability and reusability. This work gives a valuable modification pathway for the establishing multi-channel charge carrier transport for energy conversion and environmental remediation processes. The diagram showing the photocatalytic activity of CN/STO@Pt heterostructures. [Display omitted] • The novel type II-Schottky structures of CN/STO@Pt were synthesized. • The RhB decomposition obtained 90% within 60 min under visible-light-driven. • The photocatalytic H 2 evolution rates reached 10,005 μmol h−1 g−1. • The photocatalytic activity of the ternary sample remains stable after four cycles. [ABSTRACT FROM AUTHOR]

The sluggish oxygen evolution reaction (OER: 4OH− → O 2 + 2H 2 O + 4e−, E = 1.23 V vs RHE) retards the large-scale hydrogen production. Replacing OER with low-potential ethylene glycol oxidation reaction (EGOR) to drive water splitting is a promising approach to solve the high energy consumption in hydrogen production. Herein, we report an energy-efficient electrocatalytic water splitting system by using a heterostructure Ni(OH) 2 /MnO aerogel catalyst (NiMn AG) that replaces OER with ethylene glycol oxidation reaction (EGOR), resulting in the co-production of value-added formate and green hydrogen. Owing to the optimized electron distribution on the heterostructure interface, the NiMn AG catalyst exhibits excellent EGOR catalytic performance, with an overpotential of only 290 mV at 100 mA cm−2. The open-circuit potential of the reaction is reduced to 0.86 V for EGOR, rendering an earlier occurrence of electron transfer. The ion chromatography (IC) result demonstrates a highly selectivity (96%) for formate in EGOR. The density functional theory (DFT) calculations show that the interfacial effects between Ni(OH) 2 and MnO optimizes the surface energy states of NiMn AG, improving the adsorption efficiency of the reaction intermediates for EGOR and further promoting the efficient cleavage of C–C to form formate. Additionally, the incorporation of MnO stabilizes the overall energy state during violent bond-breaking processes. This work sheds light on a new methodology to design bimetallic catalysts assisted by EGOR for decoupled green hydrogen production. Porous Ni(OH) 2 /MnO@Ni (NiMn AG) is synthesized by sol-gel method and vacuum drying process and act as an anode catalyst for EGOR, to achieve value-added oxidation process of ethylene glycol, and provide electron for HER process at a low potential. The catalyst system only required 1.4 V for 20 mA cm−2, which is 292 mV lower than traditional water electrolysis. [Display omitted] • In-situ formation of Ni(OH) 2 /MnO heterostructure optimizes reactants adsorption. • Excellent ethylene glycol oxidation activity and stability at high current density. • High Faradaic efficiency and selectivity of the formate and hydrogen products. [ABSTRACT FROM AUTHOR]

This study comprehensively evaluates a bioethanol steam reforming plant in Colombia for green hydrogen (H 2) production, sourced from the country's sugar industry. By integrating experimental data and Aspen Plus simulations, the research examines the techno-economic and environmental aspects of utilizing bioethanol as a renewable feedstock for H 2 production. Rigorous process modeling, capital investment appraisal, operational cost estimation, economic performance metrics, and environmental assessment are considered. Key findings indicate an H 2 yield of 0.155 kg/kg of bioethanol and 34 % energy efficiency, eliminating reliance on fossil fuels. The Levelized Cost of Hydrogen (LCOH) at a Colombian sugar mill is calculated at 10.27 USD/kg under specific assessment conditions. The process exhibits a carbon footprint of 2.16 kg CO2-eq /kg H2 from an environmental perspective. These results emphasize the potential of bioethanol steam reforming as a sustainable and economically viable pathway for green-H 2 production, advancing energy transition efforts away from fossil fuels. [Display omitted] • Bioethanol from Colombia's sugar industry has been used for producing hydrogen. • Minimum processing capacity of bioethanol should be 156 million liters per year. • Main LCOH drivers consist of CO 2 capture CAPEX and bioethanol's market price. • The economic analysis revealed a possible LCOH of 10.27 USD/kg. • The process exhibits a carbon footprint of 2.16 kg CO 2 /kg H 2. [ABSTRACT FROM AUTHOR]

In response to climate change and the imperative for sustainable energy solutions, this study investigates the feasibility of producing green hydrogen and associated e-fuels (methane, methanol, and ammonia) using a renewable energy hybrid system in Dakhla, Morocco. Utilizing the System Advisor Model (SAM) software for simulation-based analysis, the research evaluates a hybrid system combining concentrated solar power (CSP) and photovoltaic (PV) plants against standalone counterparts. Various simulations comparing standalone PV and CSP plants with a novel CSP/PV hybrid concept were carried out. The hybrid system demonstrates significant promise, exhibiting increased annual energy yield and capacity factors up to 90%, leading to enhanced efficiency, performance, and cost savings with a Levelized Cost of Electricity (LCOE) approximating 17 cents/kWh. Furthermore, this paper conducts an in-depth exploration into the feasible production of hydrogen and its derived synthetic fuels utilizing hybrid renewable systems. The study provides a thorough examination of the production processes, yields, and efficiencies of hydrogen and its derivative e-fuels, with a focus on green hydrogen production through water electrolysis, CO2 hydrogenation, the Sabatier process, and the Haber-Bosch process. It sheds light on the potential applications of these fuels in the transportation sector, including in electric and hydrogen vehicles and aviation. The insights garnered are indispensable for crafting future strategies and policies in sustainable energy planning. These findings not only provide valuable direction for forthcoming initiatives in renewable energy but also underscore the pivotal role of hybridization in enhancing the efficient production and utilization of hydrogen within both renewable energy and transportation sectors. • PV and CSP systems to generate electricity for the Dakhla city was investigated. • A Hybrid system optimization has been proposed. • The Electricity surplus was used to produce hydrogen and hydrogen-based products. • Various scenarios for the heavy-duty application of e-fuel were presented and discussed. [ABSTRACT FROM AUTHOR]

Green hydrogen is central to the global energy transition. This paper introduces a renewable hydrogen production system model that optimizes hydrogen production on a worldwide 50 km × 50 km grid, considering country-specific investment risks. Besides the renewable energy's impact on the hydrogen production system (HPS) design, we analyze the effect of country-specific interest rates on the levelized cost of hydrogen (LCOH) production. Over one-third (40.0%) of all cells have an installed solar PV capacity share between 50% and 70%, 76.4% have a hybrid (onshore wind and solar PV) configuration. Hydrogen storage is deployed rather than battery storage to balance hydrogen production via electrolysis and hydrogen demand. Hybrid HPSs can significantly reduce the LCOH production compared to non-hybrid designs, whereas country-specific interest rates can lead to significant increases, diminishing the relative competitiveness of countries with abundant renewable energy resources compared to countries with fewer resources but fewer investment risks. [Display omitted] • Worldwide levelized cost of hydrogen production on a 50 km × 50 km grid resolution. • Impact of country risk premiums on the levelized cost of hydrogen production. • Cost-optimal hybrid hydrogen production system design per grid cell. • All results are available on an open-data license. [ABSTRACT FROM AUTHOR]

Transitioning to a sustainable energy future necessitates innovative storage solutions for renewable energies, where hydrogen (H₂) emerges as a pivotal energy carrier for its low emission potential. This paper explores unlined rock caverns (URCs) as a promising alternative for underground hydrogen storage (UHS), overcoming the geographical and technical limitations of UHS methods like salt rock caverns and porous media. Drawing from the experiences of natural gas (NG) and compressed air energy storage (CAES) in URCs, we explore the viability of URCs for storing hydrogen at gigawatt-hour scales (>100 GWh). Despite challenges such as potential uplift failures (at a depth of approximately less than 1000 m) and hydrogen reactivity with storage materials at typical conditions (below temperatures of 100°C and pressures of 15 MPa), URCs present a flexible, scalable option closely allied with green hydrogen production from renewable sources. Our comprehensive review identifies critical design considerations, including hydraulic containment and the integrity of fracture sealing materials under UHS conditions. Addressing identified knowledge gaps, particularly around the design of hydraulic containment systems and the interaction of hydrogen with cavern materials, will be crucial for advancing URC technology. The paper underscores the need for further experimental and numerical studies to refine URC suitability for hydrogen storage, highlighting the role of URCs in enhancing the compatibility of renewable energy sources with the grid. • Detailed exploration of unlined rock cavern (URC) technology. • Analysis of URCs' potential for large-scale hydrogen storage. • Insights from historical use of URCs in compressed gas storage. • Examination of the opportunities and challenges in using URCs for hydrogen storage. [ABSTRACT FROM AUTHOR]

The most economical and efficient method to produce green hydrogen relies on electrochemistry, the electricity for which is of a green origin, and on photocatalytic water splitting. The latter technology involves the use of a photocatalyst or a photo-electrocatalyst to transform solar energy into chemical energy. Vast efforts have thus been dedicated to the pursuit of such a catalyst. The current study focused on the development of a heterogeneous photoelectrochemical system in which the Na 3 [Ru 2 (μ -CO 3) 4 ] complex was used as a WOC. To that end, two types of electrodes were prepared: coated indium tin oxide (ITO) and meta-chemical surface (MCS) electrodes. Under 420 nm illumination, both electrode types exhibited higher catalytic currents than were observed without light. Our novel application of the Na 3 [Ru 2 (μ -CO 3) 4 ] complex as a catalyst in the photoelectrochemical water oxidation reaction requires minute amounts of the complex. The study findings add to the knowledge about the water-splitting process, and ultimately, they may facilitate the broader adoption of hydrogen as an environmentally friendly and increasingly accessible energy source. The Na 3 [Ru 2 (μ -CO 3) 4 ] complex is used as a WOC in electrochemical and photoelectrochemical water oxidation reactions showcasing elevated k cat values under 420 nm illumination. [Display omitted] • Initial usage of Na 3 [Ru 2 (μ -CO 3) 4 ] complex as a catalyst in photoelectrochemical water oxidation. • The working electrodes, made with minute amounts of catalyst, were stable and recyclable. • The prepared meta-chemical surface electrodes sustain a large surface area, which promotes the complex electrocatalytic activity. [ABSTRACT FROM AUTHOR]

The present study investigates the viability of employing Solar parabolic trough collectors (PTC) and parabolic dish collectors (PDC) integrated with thermal energy storage (TES) as the primary heat source for a steam-powered Rankine cycle, aimed to produce 5500 kW power for green hydrogen generation. A techno-economic analysis finds the system's overall efficiency (solar input to generator output) as 15.06% with PTC and 18.80% with PDC. Besides, incorporating PTC with binary and ternary salts in the proposed system yields approximately 22.7 % lower capital costs and a 7.8 % shorter payback period than solar PDC. Likewise, the levelized hydrogen cost with these options is around 12.3 % lower than those of PDC across all zones. However, to sustain a maximum annual hydrogen production of 238.38 tonne, equivalent to an annual electricity generation of 11180.07 MWh in each zone, the required PTC area is approximately 24.85% larger than PDC area. • Concentrated Solar Power (CSP) technologies with TES systems are utilized for hydrogen production. • System's overall efficiency (solar to electric) is found to be 14.68 % with PTC and 18.33% with PDC. • The economic analysis compares the system's capital cost, payback period, and the levelized cost hydrogen production. • Month-wise hydrogen production is presented in the different Indian climatic zones. [ABSTRACT FROM AUTHOR]

All diesel-only trains in the UK will be phased out by 2040. Hydrogen and ammonia emerge as alternative zero-carbon fuel for greener railway. Solid Oxide Fuel Cells (SOFCs) provide an alternative prime mover option, which efficiently convert zero-carbon fuels into electricity without emitting nitrogen oxides (NOx), unlike traditional engines. Superior to Proton Exchange Membrane Fuel Cells (PEMFCs) in efficiency, SOFCs fulfil MW-scale power needs and can use ammonia directly. This study investigates innovative strategies for integrating SOFCs into hybrid rail powertrains using hydrogen or ammonia. Utilizing an optimization framework incorporating Particle Swarm Optimization (PSO), the study aims to minimize operational costs while considering capital and replacement expenditures, powertrain performance, and component sizing. The findings suggest that hybrid powertrains based on ammonia-fueled SOFCs may potentially reduce costs by 30% compared to their hydrogen counterparts, albeit requiring additional space for engine compartments. Ammonia-fueled SOFCs trains also exhibit a 5% higher efficiency at End-of-Life (EoL), showing less performance degradation than those powered by hydrogen. The State of Charge (SoC) of the batteries in range of 30–70% for both cases is identified as most cost-effective. • A MW-scale solid oxide fuel cell (SOFC) hybrid freight train system utilizing either hydrogen or ammonia is proposed. • Performance analysis demonstrates the feasibility of SOFCs as a powertrain for freight trains. • Ammonia-fueled SOFCs exhibit potential for significant cost and performance benefits. [ABSTRACT FROM AUTHOR]

This study investigates the impact of including (or neglecting) the variable efficiency of hydrogen electrolyzers as a function of operating power in the modelling of green hydrogen produced from variable renewable energy sources. Results show that neglecting the variable electrolyzer efficiency, as is commonly done in studies of green hydrogen, leads to significant overestimation of hydrogen production in the range of 5–24%. The effects of the time resolution used in models are also investigated, as well as the impact of including the option for the electrolyzer to switch to stand-by mode instead of powering down and electrolyzer ramp rate constraints. Results indicate that these have a minor effect on overall hydrogen production, with the use of hour resolution data leading to overestimation in the range of 0.2–2%, relative to using 5-min data. This study used data from three solar farms and three wind in Australia, from which it is observed that wind farms produced 55% more hydrogen than the solar farms. The results in this study highlight the critical importance of including the variable efficiency of electrolyzers in the modelling of green hydrogen production. As this industry scales, continuing to neglect this effect would lead to the overestimation of hydrogen production by tens of megatonnes. • Variable efficiency electrolyzers are compared to fixed efficiency electrolyzers. • Fixed efficiency can lead to overestimation in hydrogen production by up to 24%. • Low fidelity time resolution has a modest impact on modelling hydrogen production. • Fixed efficiency electrolyzers underestimate the optimal size of hydrogen plant. • Results are validated using data from six renewable energy sites in Australia. [ABSTRACT FROM AUTHOR]

This study investigates the environmental and financial implications of an offshore wind-driven green hydrogen generation system using Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) methodologies. Global Climate Models (GCM) are employed to predict wind speeds crucial for system efficacy, followed by sizing the electrolyser system based on projected offshore wind power output. As a result of this study, LCA utilizing the GREET 2023 reveals a Global Warming Potential (GWP) of 0.7 kgCO 2 -eq./kgH 2 and 0.753 kgCO 2 -eq./kgH 2 for GWP-20 and GWP-100, respectively. Fine Particulate Matter Formation (FPMF) is calculated as 0.24 gPM 2.5 /kgH 2 for FPMF-20 and 0.53 gPM 2.5 /kgH 2 for FPMF-100. In LCCA, under the base scenario, the Net Present Cost (NPC) and Levelized Cost of Hydrogen (LCOH) are estimated at $49.65 million and $4.36/kgH 2 , respectively. Despite various incentives and tax scenarios explored, it is revealed that Internal Rates of Return (IRRs) fall below the anticipated cost of equity, indicating non-profitability. • Environmental and economic evaluation of offshore wind-driven hydrogen production. • Among all components, the spar-buoy system is responsible for the highest GWPs. • GWPs of the electrolyser system are almost negligible compared to the wind turbine. • Hydrogen production from the proposed system is not feasible without any incentive. • IRRs fall below anticipated cost of equity; tax incentives crucial for profitability. [ABSTRACT FROM AUTHOR]

The first part of the current study highlights the importance of developing a clean hydrogen supply chain (CHSC) in Iran to enhance energy security and contribute to global efforts towards sustainable energy transition. Depending on whether the focus is on domestic consumption or export of hydrogen, the study provides valuable insights into the prioritization of CHSC development pathways via multi-criteria decision-making tools (AHP, AHOP-TOPSIS, and AHP-VIKOR). The results show that for domestic hydrogen consumption (internal scenario), the best path of the supply chain includes blue hydrogen from steam methane reforming coupled with carbon capture and storage, H 2 -carriers (ammonia and methanol), natural gas grid for transportation and distribution, and industry sector as the end user. In the external scenario, however, the best path of the CHSC consists of green hydrogen production based on solar energy, and the other parts of the path include liquid hydrogen as the storage method, ship as the distribution and transportation, and industrial sector as the end user. By identifying the most suitable methods and technologies for each stage of the supply chain, this paper offers a comprehensive analysis that can guide decision-making in CHSC development. [ABSTRACT FROM AUTHOR]

There is a great desire to integrate multiple energy systems by forming low-carbon energy hubs. Among various energy platforms, the integration of power and gas networks via Power-to-Gas (PtG) technologies is introduced as a promising solution to enhance the flexibility of power grids and facilitate seamless adoption for high penetration levels of renewable energy resources. In addition, the production of green hydrogen from waste/inexpensive clean electricity has recently been identified as a potential means for large-scale energy storage, deployment of hydrogen mobility, and decarbonization of several processes that utilize hydrogen. As integrated hydrogen-based energy hubs (H 2 Hubs) attract more attention for widespread deployment, the security of such new platforms against various cyberattacks is also becoming a critical topic for investigation. This paper proposes a new data estimation technique, developed and integrated with H 2 Hubs scheduling models, for real-time optimal adaptive collection and organization of the system operating parameters for cybersecurity assessment. A new formulation is presented for the adaptive formation of a newly proposed concept, referred to as the system feasibility area , via real-time acquisition of the system operating information. The created feasibility areas are utilized for real-time post-occurrence detection of the bad scheduling data that is invisible to the existing cybersecurity layers. Numerical studies are conducted to demonstrate the efficacy and feasibility of the proposed model. The results demonstrate that the historical data can be adaptively collected in real time and successfully utilized to create feasibility areas to categorize the system operating points. • An optimal scheduling model is proposed for hydrogen-based energy hubs (H 2 Hubs). • A new data estimation method is developed and integrated with the scheduling model. • A new formulation is given for the adaptive creation of the feasibility area. • Simulation case studies are presented and discussed. [ABSTRACT FROM AUTHOR]

Hydrogen has been widely recognised as a key resource in transitioning towards a sustainable and decarbonised energy future. Of the available hydrogen production processes, solid oxide electrolysis is a promising way to produce green hydrogen via high temperature electrolysis. The high conversion efficiencies of solid oxide electrolysis systems combined with the ability to integrate this technology with downstream chemical syntheses plants make them very attractive compared to other electrolysis technologies. However, solid oxide electrolysis, to date is the least developed electrolysis technology from the point of view of large-scale commercialisation. In recent years, significant research on fabrication and testing of individual solid oxide electrolyser (SOE) cells has been reported which has led to a multi-fold improvement in cell performance. Improvements on a cell level, though do not directly translate to improvements on a stack and system-level scale. Scaling-up solid oxide electrolysers for higher hydrogen production rates is challenging. This review presents an overview of the experimental and modelling investigations of the stack and system-scale SOE technology. The current commercial status of the SOE systems is highlighted and further improvements needed for successful near and long-term commercialisation of the technology are discussed. [Display omitted] • Solid oxide electrolyser systems are reviewed, with a focus on stacks and modules. • Experimental studies on solid oxide stack testing are discussed. • Numerical and system-level modelling-based studies are reviewed in depth. • Current status of commercial solid oxide electrolyser systems is highlighted. • Challenges and future outlook for the technology are discussed. [ABSTRACT FROM AUTHOR]

The current study reviews recent developments in hydrogen production methods. Also, the study seeks to take a step forward by comparing the methodology, energy entering each cycle, hydrogen production rate, production cost rate, environmental impacts, and energy and exergy efficiency in recent years. Hydrogen production methods are categorized based on initial energy resources. The resources are categorized into fossil fuel and renewable groups. Among fossil fuel-based techniques, steam reforming is the most frequently used approach, with a hydrogen production rate above 80%. Renewable resources for hydrogen production methods are grouped into water and biomass. For the water group, water splitting is performed by electrolysis technology, and for the biomass group, gasification is widely used due to higher efficiency and positive environmental effects. When the hydrogen production methods were introduced, 50 recent studies on hydrogen production methods were comprehensively compared. The studies were evaluated according to their different hydrogen production methods, including liquefaction, pyrolysis, gasification, combustion, solid oxide, alkaline, and polymer electrolyte membrane, all of which are renewable source-based technologies, needless of large and costly infrastructure. However, thermochemical methods, such as steam methane, pyrolysis reforming, etc., are justifiable for evaluation due to different challenges, including production efficiency, type of raw materials, and production purification, etc. The hydrogen green index (HGI) was introduced to better compare the sustainability and environmental impacts of the recent literature. As a dimensionless parameter, HGI is the rate of hydrogen production to CO 2 reduction per 1 USD. Although common comparison methods consider PEM as the best hydrogen production method, HGI suggests that SMR is the best option (HGI = 4.19). • The recent developments in hydrogen production methods is evaluated in this study. • Introducing HGI for eco-sustainability evaluation. • Steam reforming prevails among fossil fuel methods, yielding 80% hydrogen. • PEM and SMR have been used more than other methods in recent years. • The maximum CO2 reduction per one USD was obtained by PEM (equal to 8.58 kg/USD). [ABSTRACT FROM AUTHOR]

Herein, we present the production of either dimethyl ether (DME), methyl formate (MF) or dimethoxymethane (DMM), representing pivotal molecules for the green transformation of fuels and chemical industry, by the non‐oxidative gas‐phase conversion of methanol under the same reaction conditions. The product selectivity is optimized by tailoring the acidic and dehydrogenative sites of the bifunctional Cu/Hβ catalyst system by varying the SiO2/Al2O3 ratio of the Hβ zeolite (25 and 520) and the Cu loading (0.5 and 20 wt %). At 240 °C, >99 % (DME), 74.5 % (MF), and 77.3 % (DMM) selectivity is achieved with the respective catalysts 0.5 %Cu/Hβ(25), 20 %Cu/Hβ(520), and 0.5 %Cu/Hβ(520). High acidic site concentration catalyzes DME formation, while the presence of Cu+ species is crucial for DMM formation, and Cu0 species mainly catalyze MF formation. A highly dynamic reaction behaviour is observed, when the dehydrogenative functionality is dominant (i. e. in the production of MF or DMM), presumably due to the dynamic nature of the Cu oxidation state, which is in turn influenced by possible by‐products (H2 and H2O). While the catalytic activity in DME synthesis over 0.5 %Cu/Hβ(25) is remarkably stable over 1500 min TOS, the activity in MF and DMM production over 20 %Cu/Hβ(520) and 0.5 %Cu/Hβ(520), respectively, can be successfully regenerated. [ABSTRACT FROM AUTHOR]

In pursuing green hydrogen fuel, electrochemical water-splitting emerges as the optimal method. A critical challenge in advancing this process is identifying a cost-effective electrocatalyst for oxygen evolution on the anode. Recent research has demonstrated the efficacy of first-row transition metal carbonates as catalysts for various oxidation reactions. In this study, Earth-abundant first-row transition metal carbonates were electrodeposited onto nickel foam (NF) electrodes and evaluated for their performance in the oxygen evolution reaction. The investigation compares the activity of these carbonates on NF electrodes against bare NF electrodes. Notably, Fe2(CO3)3/NF exhibited superior oxygen evolution activity, characterized by low overpotential values, i.e. Iron is master of them all (R. Kipling, Cold Iron, Rewards and Fairies, Macmillan and Co. Ltd., 1910). Comprehensive catalytic stability and durability tests also indicate that these transition metal carbonates maintain stable activity, positioning them as durable and efficient electrocatalysts for the oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

Lithium sulfide (Li2S) is the critical raw material used for the synthesis of sulfide solid-state electrolytes, but its high cost and pollution restrict the commercialization of sulfide solid-state electrolytes and sulfide-based all-solid-state batteries. A new green and cost-effective method for the synthesis of high-quality Li2S is designed and proposed in this work. The method of reducing Li2SO4 with H2 circumvents the disadvantages of many side reactions, complicated purification processes, impure products and emission of greenhouse gases (CO and CO2) associated with traditional carbothermal reduction methods, and high-purity Li2S (H-Li2S) is obtained. Subsequently, H-Li5.6PS4.6Cl1.4 solid electrolyte was synthesized and compared with the C-Li5.6PS4.6Cl1.4 electrolyte synthesized from commercial Li2S (C-Li2S). The ionic conductivity (8.06 mS cm−1) and chemical/electrochemical stability as cathode/anode material were better than those of C-Li5.6PS4.6Cl1.4. Besides, the rate performance and long cycling stability of an all-solid-state lithium battery NCM//Li5.6PS4.6Cl1.4//Li–In assembled with H-Li5.6PS4.6Cl1.4 are better than those of batteries assembled with C-Li5.6PS4.6Cl1.4. It can maintain a discharge capacity of 133.23 mA h g−1 after 300 cycles at 1C (95% of the initial discharge capacity), and has a high discharge capacity of 127.9 mA h g−1 at 3C. The high electrochemical performance of the all-solid-state battery confirms the superiority of high-purity H-Li2S and the advantages of the hydrogen reduction method. [ABSTRACT FROM AUTHOR]

Lignin, a crucial component of lignocellulosic biomass, holds immense promise for advancing biorefineries and producing sustainable energy alternatives. This study engineered a CN/rGO/BMO (2 : 1) heterojunction photocatalyst with varying Pd NP loading to selectively target the hydrogenolysis of challenging C–O ether bonds in lignin model compounds. Specific focus was on β-O-4, α-O-4, and the formidable 4-O-5 linkages. The 4-O-5 linkage, due to its high dissociation energy, poses a significant challenge. Electrochemical and spectral analyses unveiled improvements in charge separation, leading to delayed recombination of charge carriers in the heterojunction photocatalyst. Decorating the heterojunction with Pd NPs exhibited an elevated work function and a low Fermi energy level, facilitating the accommodation of photogenerated electrons and enabling efficient H2 dissociation. Such enhancement facilitated the cleavage of all three linkages, including the resistant 4-O-5 bonds under ambient conditions. The photocatalyst exhibited effective cleavage, yielding aromatic (toluene, phenol, ethylbenzene) and aliphatic (cyclohexane, ethylcyclohexane) products. Selectivity modulation was achieved by adjusting the time, hydrogen pressure, and Pd loading. Furthermore, this photocatalytic approach successfully transformed simulated lignin bio-oil containing all three linkages into valuable monomers. The alcoholic solvents efficiently harnessed photogenerated holes and prevented electron–hole recombination. The photocatalyst also demonstrated the capability to produce monomers from the native lignin extracted from teak wood sawdust. Emphasizing the focus on the reaction pathway and mechanism, scavenging studies and analyses were conducted, including UPS and VBXPS, to establish the Z-scheme charge transfer mechanism within the heterojunction. These findings provide a sustainable and efficient pathway for lignin valorisation in biorefineries, significantly contributing to the advancement of green fuels and aligning with the principles of green chemistry. [ABSTRACT FROM AUTHOR]

A new catalytic transfer hydrogenation (CTH) strategy was developed for the continuous conversion of furfural (FF) into furfuryl alcohol (FFA) with Cu/ZnO/Al2O3 (CZA) as the catalyst under mild conditions. Methanediol was used as the hydrogen donor without any hazardous gas emission. FF was converted into FFA with up to 99% selectivity at 108 °C and normal pressure under an N2 atmosphere. The highly dispersive copper species (Cu0, Cu+) with few Lewis acidic sites and η1(O)-type adsorption ensured high selectivity and mild conversion. Deuterium-labelling experiments revealed that, in the presence of formaldehyde, water is split into hydrogen species, which can reduce FF to form FFA. A reasonable reaction mechanism for the conversion of FF into FFA via transfer hydrogenation was proposed. Notably, this strategy offers a new route to splitting water to generate in situ "green hydrogen" for the hydrogenation of unsaturated organic compounds under mild conditions based on non-noble heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

Electro-catalytic water splitting is widely viewed as an efficient and viable strategy for green hydrogen production. Herein, we designed nanostructured nickel–cobalt alloy grown on the reduced graphene oxide-single walled carbon nanotube (rGO-SWCNT) thin film by means of electro-deposition, which was used to catalyze water splitting for hydrogen evolution reaction (HER) in an alkaline medium. It was found that the HER performance of nickel–cobalt alloys was determined by the Co/Ni ratio and better than their corresponding single components Co and Ni. Nickel–cobalt alloy with a Co/Ni ratio of 2 (CoNi21) exhibited the most notable HER efficiency with an overpotential of 83.5 mV and 291.8 mV vs. reversible hydrogen electrode at 10 mA cm−2 and 100 mA cm−2, respectively. Furthermore, the significantly lower Tafel slope (112.6 mV dec−1) of CoNi21 indicates that the HER kinetics of the nickel–cobalt alloy is accelerated due to the synergistic effect of Ni and Co. The charge-transfer resistance of CoNi21 is significantly low compared to any single component, validating the intensified interfacial charge transfer. Besides, CoNi21 has the highest active surface area of 147.1 mF cm−2 on the basis of the ECSA measurements, which can be beneficial for providing rich active sites. The CoNi21 catalyst offered excellent durability for HER in the alkaline medium. This work provides a combinatorial method integrating rich interfaces of Co–Ni alloy on highly conductive carbon substrate to design efficient and low-cost electrocatalysts for improving the HER performance. [ABSTRACT FROM AUTHOR]

Green hydrogen production is a promising solution for the effective and economical exploitation of floating offshore wind energy in the far and deep sea. The inherent fluctuation and intermittency of wind power significantly challenge the comprehensive performance of the water electrolysis systems and hydrogen post-processing systems. Effective coordination with energy storage, including both electricity energy storage and hydrogen energy storage, can mitigate these challenges. Subsea energy storage is an emerging and promising alternative to conventional floating onboard energy storage. In this review, various potential subsea electricity and hydrogen energy storage solutions for 'floating offshore wind + hydrogen' are examined and compared. Many advantages, including security, energy efficiency, economy, lifecycle, and management, can be brought about if the energy storage systems are deployed at the seabed. In particular, integrating intermediate energy storage between the wind farm and hydrogen production plant will allow the expensive electrolyzers to be sized for a high utilization factor and reduce the degradation of electrolyzer performance. Recommendations are provided by analyzing the advantages and disadvantages of these energy storage options. Analysis of policy and market indicates that the period from 2024 to 2030 will be critical for the long-term competition of subsea energy storage with floating energy storage. Overall, subsea energy storage can be a promising enabler for emerging floating offshore wind hydrogen production. This review is intended to arouse extensive discussion and investigation on this topic. [Display omitted] • Energy storage is essential for producing green hydrogen from offshore wind. • Floating and subsea electricity and hydrogen energy storage are compared and discussed. • There is still no commercially acceptable energy storage solution. • The critical development period for subsea energy storage is from 2024 to 2030. [ABSTRACT FROM AUTHOR]

The production of hydrogen from residual biomass represents a sustainable alternative to integrate the production of renewable hydrogen in coming years. This work shows the results obtained during an experimental campaign dedicated to analysing the performance of a downdraft gasifier of about 100 kW t fed with woody biomass and oxy-steam mixtures. With suitable oxygen-steam ratios it was possible to produce a syngas with a hydrogen content higher than 40%vol, with a cold gas efficiency of more than 80%. The experimental syngas composition is used as input of a numerical model, created in Aspen Plus® and dedicated to evaluating the performance of the plant section for the pure H 2 -production. The numerical analysis highlighted the possibility of obtaining approximately 5% by mass of hydrogen with respect to the biomass used, also evidencing how the correct use of thermal waste and residues makes the whole plant (gasifier plus hydrogenizer) independent on heat supply. • Woody biomass oxy-steam gasification has been analysed in a real-scale downdraft gasifier. • Oxy-steam gasification confirmed to be effective in increasing hydrogen yield in the syngas. • The optimum equivalence ratio and steam/biomass mass ratio have been determined. • A H 2 production plant has been conceived and analysed to exploit the produced syngas. • The study evidenced the possibility of obtaining a hydrogen/biomass mass ratio of 5%. [ABSTRACT FROM AUTHOR]

As global environmental issues become increasingly prominent, the maritime industry faces an urgent imperative to curtail carbon emissions and mitigate environmental impact. Green marine alternative fuels are actively addressing these challenges. Global patent data are collected, and four sub-technologies of green fuel technologies in the maritime field are extracted based on Natural Language Processing. To evaluate the innovation trends and evolutionary paths of these technologies, the Main Path Analysis is employed to identify the evolution path of technologies and the evolution situation of major innovative entities, while the Social Network Analysis was used to present the results visually. These four sub-technologies (Hydrogen & Fuel Cell, Methanol & Ethanol, Ammonia, and LNG & LPG) have occupied the mainstream of fuel technology in maritime over the past five years, with 34.6% of patents, 38.3% of patent citations, and 93.9% of technological influence, accounting for 27.4%, 20.5%, 16.7% and 44.3%, respectively. Ammonia, and Hydrogen & Fuel Cell are springing up like mushrooms after rain, while the development of LNG & LPG, Methanol & Ethanol is relatively mature. Each of these technologies showcases distinct developmental paradigms. We elaborated on developmental paradigms and future research priorities of each technology in the conclusion. In addition, new technological opportunities are also created through the cross-fertilization of technologies. In particular, integrated systems for hydrogen production, storage, and combustion on LNG ships, and maritime hybrid power systems driven by ammonia and hydrogen have opened a new window for the green development of maritime fuels. • Four green fuel technologies account for 93.9% of maritime fuel technological influence in the past five years. • Hydrogen & Fuel Cell and Ammonia rapidly expand, while LNG & LPG and Methanol & Ethanol are relatively mature. • This study details the unique development paradigms and future research priorities for each technology. • Hydrogen systems on LNG ships and hybrid ammonia-hydrogen maritime power open new avenues for green fuel development. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER), an important reaction involved in water splitting and rechargeable batteries, has drawn massive attention to clean energy generation, conversion, and efficient storage technologies during the last decades. However, noble metal-based highly active electrocatalysts for OER have been employed for water splitting, whereas their excessive cost and lethargic kinetics impede their usage. Bimetallic nanoparticles (NPs) have appeared as an essential class of catalysts suggesting higher catalytic efficiencies. Nickel/Iron (NiFe)-based compounds have been known as active OER catalysts by enormous commercial interest owing to their interesting mechanical, electrical, and corrosion-resistant properties. In this study, we prepared various Ni x Fe y nanoporous by reducing Ni and Fe precursors using a NaBH 4 reducing agent. The obtained catalysts show the high BET surface areas of 108.18, 122.67, 157.14, 166.65, and 244.12 (m2/g) for Ni, Ni 3 Fe 1 , Ni 1 Fe 1 , Ni 1 Fe 3 , and Fe samples; respectively. Among synthesized catalysts, it is obvious that Ni 3 Fe 1 exhibits a good OER performance with an overpotential of 220 mV or 346 mV at a current density of 10 mA. cm−2 or 50 mA. cm−2 and stability for 60,000 s due to the interaction between Ni and Fe and the exposure of more active surface area and low charge transfer electron resistance of the catalyst. This cheap and highly efficient Ni 3 Fe 1 electrocatalyst can be a promising candidate for the OER in water splitting for producing green fuel hydrogen. [Display omitted] • NiFe nanoporous materials are synthesized with large BET surface areas. • The presence of Fe enhances the BET surface area in bimetallic NiFe materials compared to pure Ni. • Electron density transfer between Ni and Fe atoms on the surface of the catalyst improves the OER activity. • Ni 3 Fe 1 shows the best OER activity during long-time operation. [ABSTRACT FROM AUTHOR]

Fuel cell electric buses (FCBs) have proven to be a technically viable solution for transportation, owing to various advantages, such as reliability, simplicity, better energy efficiency, and quietness of operation. However, large-scale adoption of FCBs is hindered by the lack of extensive and structured infrastructure and the high cost of clean hydrogen. Many studies agree that one of the significant contributors to the lack of competitiveness of green hydrogen is the cost of electricity for its production, followed by transportation costs. On the one hand, to reduce the investment cost of the electrolyzer, high operating hours should be achieved; on the other, as the number of operating hours decreases, the impact of the electricity costs declines. This paper presents an innovative algorithm for a scalable hydrogen refuelling station (HRS) capable of successfully matching and identifying the most cost-efficient levelized cost of hydrogen (LCOH) produced via electrolysis and connected to the grid, based on the HRS components' cost curves and the hourly average electricity price profile. The objective is to identify the least-cost range of LCOH by considering both the electric energy and the investment costs associated with a hydrogen demand given by different FCB sizes and electrolyzer rated powers. In addition, sensitivity analyses have been conducted to quantify the technology cost margins, and a cost comparison between the refuelling of an FCB fleet and the recharging infrastructure required for an equivalent fleet of Battery Electric Buse (BEB) has been performed. An LCOH of around 10.5 €/kg varying from 12 €/kg (2 FCB) to 10.2 €/kg (30 FCB) has been found for the best-optimized configurations. The final major conclusion of this paper is that FCB technology is currently not economically competitive. Still, a cost contraction of the electric energy price and the electrolyzer capital investment would lead to a 50% decrease in the LCOH. Furthermore, increasing renewable energies into the grid may shift the electricity cost curve, resulting in higher prices when the BEB recharging demand is more significant. This impact, in addition to the peak power load and longer recharging times, might contribute to bridging the gap with FCBs. • Techno-economic model for the sizing of an HRS with grid-connected electrolyzer. • The widespread diffusion of H2 technology in mobility needs both reliability and cost-effectiveness. • Investigation of various electrolysers rated powers and fuel cell buses fleet size. • An action on both CAPEX and OPEX would lead to potential cost margins improvement. • It is found that the best configuration that balances the CAPEX and OPEX coincides with an LCOH ranging from 12 to 10 €/kg. [ABSTRACT FROM AUTHOR]

In response to the rapidly changing industry caused by climate change, the Korean government has set a goal of supplying 3 million tons of green hydrogen by 2050. This study aims to determine the leveled cost of hydrogen (LCOH) resulting from floating offshore wind power generation. Initially, we created a numerical model to represent the power curve for large-capacity offshore wind power generation. Additionally, we accounted for the variability in electrolytic cell efficiency by modeling predictions based on real PEMEC parameters using the Aspen Custom Model. The power-hydrogen quantity was then predicted using Aspen Plus. A comparison is also made regarding the transportation of gaseous hydrogen and liquid hydrogen. Gaseous hydrogen is produced through pipelines, while liquid hydrogen is produced using a modified Claude cycle and transported via trucks. Finally, a Techno-economic analysis was conducted, considering the net present value (NPV) derived from capital expenditure (CAPEX) and operating expenditure (OPEX) throughout the entire process. The analysis of LCOH indicated that the most economically viable option for the region with the lowest LCOH per kg is the supply of liquid hydrogen, priced at $11.04/kgH 2. Our sensitivity analysis also reveals that while liquid hydrogen is more cost-effective at up to 250 MW, gaseous hydrogen becomes cheaper as its scale exceeds 500 MW because of its greater sensitivity to production volume. • Developed a new model that integrates real-time wind data for optimizing hydrogen production from offshore wind power. • LNG cold heat recovery significantly reduced the cost of liquefied hydrogen obtained from floating offshore wind farms. • Sensitivity analysis shows that liquid hydrogen is more cost-effective up to 250 MW while gaseous hydrogen is cheaper above 500 MW. [ABSTRACT FROM AUTHOR]

The development of active single-atom catalysts for the alkaline hydrogen evolution reaction (HER) offers a promising strategy for lowering the cost of green hydrogen. Pt single atoms were in-situ anchored on layered double hydroxide (CoFeLDH) nanosheets using CV scanning electrodeposition with an optimal 40 cycles. The HAADF-STEM analysis confirmed the monoatomic dispersion of Pt in the CoFeLDH-Pt 40cls catalyst, whereas XAFS showed that Pt was coordinated with four oxygens. Density functional theory calculation revealed a drop in the reaction energy barrier of the rate-limiting Volmer step during water splitting over the CoFeLDH-Pt 40cls catalyst from 2.28 to 1.78 eV. Additionally, the free energy for hydrogen desorption decreased from 1.52 to −0.02 eV. The CoFeLDH-Pt 40cls catalyst demonstrated excellent HER kinetics by achieving a −10 mA/cm2 current density at 45 mV overpotential. It also exhibited sustained high activity for around 100 h in stability studies. Synthesis of in-situ anchored Pt single atom catalyst CoFeLDH-Pt 40cls for alkaline HER. [Display omitted] • Pt single atoms were in-situ anchored on CoFeLDH nanosheets through electrodeposition for HER. • The CoFeLDH-Pt 40cls exhibited a low overpotential of 45 mV at 10 mA/cm2. • HAADF-STEM and XAFS confirmed the monoatomic Pt in CoFeLDH-Pt 40cls. • DFT calculations showed that Volmer step decreased from 2.28 eV to 1.78 eV. [ABSTRACT FROM AUTHOR]

Efficient and stable catalysts are crucial for green hydrogen production from acidic water splitting. Herein, using interface engineering, the surface electronic structures of bimetallic PdRu nanocubes have been significantly regulated by Pt atoms (PdRu@Pt). Interestingly, Pt atoms are located on the corners and facets of PdRu nanocubes, resulting in lattice tension and fast electron transfer. As a result, the obtained trimetallic PdRu@Pt nanocubes with an average size of 13 nm have exhibited highly enhanced catalytic activity and stability for hydrogen evolution reaction (HER) in acidic media, delivering 18 mV lower overpotential to reach a current density of 10 mA cm−2, and maintaining a remarkable long-term stability for up to 24 h. In particular, the lower overpotential of 489 mV at 500 mA cm−2 for PdRu 0.04 @Pt 0.12 nanocubes indicates its potential for future industrial application in the future. Such enhancements in HER performance can be attributed to the highly facet-edge-exposed Pt atoms and the significant strain effects resulting from the introducing Pt atomic layers to PdRu surfaces. [Display omitted] • A facile seed-mediated straightforward approach for constructing trimetallic PdRu@Pt nanocubes. • Interface engineering inducing edge-exposed Pt atoms, tailorable electronic structures, and improved strain effects. • Significantly enhanced acidic HER activity and stability with lower overpotential of 18 mV at 10 mA cm−2 [ABSTRACT FROM AUTHOR]

A very promising alternative fuel that can take the place of present fossil fuels is ammonia. Given that it is a hydrogen carrier with no carbon-based emissions and can be manufactured using renewable sources, it is a green fuel for Internal Compression Engine (ICE) with promising future applications. The notion of using pure ammonia in fueling combustion engines is not new, but despite numerous studies that looked into the possibility, Combustion engine fueling techniques based on ammonia are not yet ready for commercialization. This is because using this toxic molecule still presents significant challenges due to its supply, safety concerns, and physical differences from conventional fossil fuels. The objective of this review is to provide readers with a broad overview of the green ammonia research as a potential replacement fuel for ICE, as well as a look at potential future uses and workable solutions to related issues. The physicochemical characteristics of ammonia are discussed to determine the key benefits and drawbacks of its application in combustion engines, with an emphasis on the difficulties, advantages, and potentials for the future as well as recent technological advancements to get around the obstacles related to its production, storage, and utilization. Additionally, this work delves into sustainable approaches for the production of green ammonia and its application in spark ignition (SI) and compression ignition (CI) engines. Within this context, this study elucidates the foundational principles, research findings, practical considerations, economic implications, and prospective outlook towards a paradigm shift wherein ammonia assumes a significant role as a primary energy source in combustion engines. More study of ammonia combustion phenomena is necessary to propose solutions to these problems. This overview clarifies recent developments in ammonia technology from the point of manufacture to the point of consumption. [Display omitted] • A comprehensive review on NH 3 as a potential fuel in internal combustion engine (ICE). • Assessed physiochemical properties and different sustainable NH 3 production methods. • Spark ignition and compression ignition engines can work with NH 3 only or NH 3 dual-fuel. • Studies are required to ensured complete NH 3 combustion and to address NO x formation issues. [ABSTRACT FROM AUTHOR]