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This study investigates the impact of biaxial strain on monolayer black phosphorus (BP) through first-principles calculations, confirming its stability and subsequently modifying its photocatalytic performance. Under biaxial strain, BP exhibits a direct bandgap suitable for photocatalytic hydrogen production during water splitting, albeit with limitations due to its valence band maximum edge. A distinctive GaN/BP heterojunction is proposed, featuring a direct bandgap and advantageous band edge positions conducive to efficient photocatalytic overall water splitting. Under the influence of biaxial strain, the heterojunction type undergoes a transition from direct type-I to direct type-II and Z, augmenting the separation of photoexcited electrons and holes and markedly enhancing the efficiency of photocatalytic hydrogen production. Furthermore, the heterojunction exhibits commendable capabilities in absorbing visible light. This research provides a promising avenue to surmount the constraints associated with monolayer BP in photocatalysis, offering valuable insights for the development of efficient photocatalytic materials. [ABSTRACT FROM AUTHOR]

Substituting slow oxygen evolution reaction (OER) with thermodynamically favorable urea oxidation reaction (UOR) is considered as one of the feasible strategies for achieving energy-saving hydrogen production. Herein, a uniform layer of NiMoO4 nanorods was grown on nickel foam by a hydrothermal method. Then, a series of Ni-MoOx/NF-X nanorod catalysts comprising Ni/NiO and MoOx (MoO2/MoO3) were prepared through regulating annealing atmosphere and reduction temperature. The optimized Ni-MoOx/NF-3 with a large accessible specific area can act as a bifunctional catalyst for electrocatalytic anodic UOR and cathodic hydrogen evolution reaction (HER). At a current density of 100 mA cm−2, the introduction of urea can significantly reduce the overpotential of Ni-MoOx/NF-3 by 210 mV compared to OER. In addition, Ni-MoOx/NF-3 has a higher intrinsic activity than other catalysts. It only requires −0.21 and 1.38 V to reach 100 mA cm−2 in HER and UOR, respectively. Such an excellent performance can be attributed to the synergistic function between Ni and MoOx. The presence of metallic Ni and reduced MoOx in pairs is beneficial for improving the electrical conductivity and modulating the electronic structure, resulting in enhancing the electrocatalytic performance. When assembling Ni-MoOx/NF-3 into an overall urea–water splitting system, it can achieve energy-saving hydrogen production and effective removal of urea-rich wastewater. [ABSTRACT FROM AUTHOR]

Plasmonic catalysis triggers the dissociation of H 2 or adsorbed O 2 (sluggish processes) under continuous wave excitation via plasmon decay. This is coupled to interband or intraband excitation of d-band or sp-band, respectively, to levels above fermi level of metals. Here, we have studied the plasmonic and photocatalytic behavior in an environment friendly medium with AM 1.5 G sunlight of CuO/ Cu 2 O thin films fabricated by pulsed laser deposition technique in vacuum with varying thickness. We have achieved ∼ 0.59 kmol h − 1 g − 1 H 2 production in the CuO/ Cu 2 O film with a thickness of ∼ 27 nm. The role of plasmons with metal–dielectric and semiconductor–semiconductor interfaces is conducted through both experimental and theoretical approaches. The results suggest that the impact of plasmonic catalysis/synthesis is subject to the dimension, composition, and band alignment of two interface materials. [ABSTRACT FROM AUTHOR]

There is growing interest in the use of hydrogen as a transportation fuel but the environmental benefits of using hydrogen depend critically on how it is produced and distributed. Leading alternatives to using fossil natural gas to make hydrogen through the conventional method of steam methane reforming include using electrolyzers to split water into hydrogen and oxygen, and the use of biogas as an alternative feedstock to fossil natural gas. This report examines the latest carbon intensity (CI) estimates for these and various other hydrogen production processes, adding important nuances to the general “colors of hydrogen” scheme that has been used in recent years. CI values for hydrogen production can vary widely both within and across hydrogen production pathways. The lowest CI pathways use biomass or biogas as a feedstock, and solar or wind power. The report also analyses jobs creation from new hydrogen production facilities and shows that these benefits can be significant for large-scale facilities based on either future biomass/biogas-to-hydrogen or solar-hydrogen production technologies. Recommendations include setting stricter goals for the state’s Low Carbon Fuel Standard (LCFS) program to continue to reduce the carbon footprint of California’s transportation fuels.

The potential of methanol reforming systems to greatly improve productivity in chemical reactors has been limited, due in part, to the effect of mass transfer limitations on the production of hydrogen. There is a need to determine whether or not a microchannel reforming reactor system is operated in a mass transfer-controlled regime, and provide the necessary criteria so that mass transfer limitations can be effectively eliminated in the reactor. Three-dimensional numerical simulations were carried out using computational fluid dynamics to investigate the essential characteristics of mass transport processes in a microchannel reforming reactor and to develop criteria for determining mass transfer limitations. The reactor was designed for thermochemically producing hydrogen from methanol by steam reforming. The mass transfer effects involved in the reforming process were evaluated, and the role of various design parameters was determined for the thermally integrated reactor. In order to simplify the mathematics of mass transport phenomena, use was made of dimensionless numbers or ratios of parameters that numerically describe the physical properties in the reactor without units. The results indicated that the performance of the reactor can be greatly improved by means of proper design of catalyst layer thickness and through adjusting feed composition to minimize or reduce mass transfer limitations in the reactor. There is not an effective method to reduce channel dimensions if the flow rate remains constant, or to reduce fluid velocities if the residence time is kept constant. The rate of the reforming reaction is limited by mass transfer near the entrance of the reactor and by kinetics further downstream, when the heat transfer in the autothermal system is efficient. Finally, the criteria that can be used to distinguish between different mass transport and kinetics regimes in the reactor with a first-order reforming reaction were presented.

Computational fluid dynamics uses numerical methods and algorithms to solve and analyse problems that involve fluid flows. Computers may be used to perform the calculations required to simulate the interaction of liquids and gasses with a surface defined by boundary conditions. Thermodynamics is the science of the relationship between heat, work, temperature, and energy. Computational modelling for microchannel reactor design was performed to investigate the effects of various factors on the efficiency and performance of an autothermal reforming system. The yield and productivity from the chemical process were determined by performing computational fluid dynamics and thermodynamic analysis. Strength and weakness were assessed under different reaction conditions. Design recommendations were provided and operation strategies were mapped out. The results indicated that operation at millisecond contact times is feasible, but optimisation of reaction conditions is necessary to balance efficiency and performance. The conversion to hydrogen is influenced greatly by the feed composition, which must be controlled precisely within certain needed limits to maximize the yield and productivity from the autothermal reforming process while avoiding the problems of combustion or explosion. Additionally, the efficiency difference between feed compositions is determined by thermodynamic analysis. The calculated output power of the autothermal reforming reactor is of the order of thousands of kilowatts per cubic meter.

[Display omitted] • Ni-NiO@CNFs/ZnIn 2 S 4 -Vs was prepared by electrospinning and solvothermal methods. • The different photothermal conversion abilities of Ni and CNFs convert NIR into heat energy. • The hydrogen production rate of the best sample (0.9Ni-NiO@CNFs/ZIS-Vs) was as high as 29.16 mmol·g−1·h−1. • Under Vis-NIR conditions, the apparent activation energy (Ea) of 0.9Ni-NiO@CNFs/ZIS-Vs is as low as 9.28 kJ·mol−1. • The photothermal conversion efficiency of the 0.9Ni-NiO@CNFs/ZIS-Vs sample is 61.42%. Photothermal synergistic catalysis is a novel technology that converts energy. In this study, ZnIn 2 S 4 with S-vacancy (ZIS-Vs) is combined with Nickel, Nickle Oxide and Carbon Nanofiber aggregates (Ni-NiO@CNFs) to create a multi-interface coupled photocatalyst with double Schottky barrier, double channel and mixed photothermal conversion effect. Theoretical calculation confirms that the Gibbs free energy (ΔG *H) of the S-scheme heterojunction in the composite material is −0.07 eV, which is close to 0. This promotes the adsorption of H* and accelerates the formation of H 2. Internal photothermal catalysis is achieved by visible-near infrared (Vis-NIR, RT) irradiation. The internal photothermal catalytic hydrogen production rate of the best sample (0.9Ni-NiO@CNFs/ZIS-Vs) is as high as 17.24 mmol·g−1·h−1, and its photothermal conversion efficiency (η) is as high as 61.42 %. Its hydrogen production efficiency is 20.52 times that of ZIS-Vs (0.84 mmol·g−1·h−1) under visible light (Vis, RT) conditions. When the Vis-NIR light source is combined with external heating (75 ℃), the hydrogen production efficiency is further improved, and the hydrogen production efficiency (29.16 mmol·g−1·h−1) is 26.75 times that of ZIS-Vs (1.09 mmol·g−1·h−1, Vis-NIR, RT). Further analysis shows that the increase in hydrogen production resulted from the apparent activation energy (Ea) of the catalyst decreasing from 16.7 kJ·mol−1 to 9.28 kJ·mol−1. This study provides a valuable prototype for the design of an efficient photothermal synergistic catalytic system. [ABSTRACT FROM AUTHOR]

The unique localized environments (Ni- N -Fe structures and unsaturated O- and N -coordination) due to dual-defect strategy can make the motif more reactive. The N -v Fe -NiFe 2 O 4 /NF catalyst containing N doping and Fe vacancies exhibits overpotentials of 210, 213 and 222 mV at 100 mA cm−2 in 1.0 M KOH, 1.0 M KOH + 0.5 M NaCl and 1.0 M KOH + seawater electrolytes, respectively. [Display omitted] Developing simple and energy-saving pathways to prepare high-efficient and robust non-noble metal based electrocatalysts remains a huge challenge to hydrogen production from seawater electrolysis. Here we demonstrate a facile hydrothermal-calcination-etching approach that simultaneously achieves the required surface N doping and Fe vacancies generation to activate the Ni-O-Fe active motifs in N -v Fe -NiFe 2 O 4 /NF. The unique localized environments (Ni- N -Fe structures and unsaturated O- and N -coordination) due to dual-defect strategy can effectively regulate the electronic structure of the Ni-O-Fe motif to make the motif more reactive. As a result, the N -v Fe -NiFe 2 O 4 /NF catalyst exhibits overpotentials of 210, 213 and 222 mV to deliver 100 mA cm−2 in 1.0 M KOH, simulated seawater and alkaline seawater environments, respectively. Theoretical calculations prove that the Ni-O-Fe structure is the active motif and that the presence of special localized environments can optimize the adsorption of key intermediates on the activated active motifs. [ABSTRACT FROM AUTHOR]

Ni-doped CoTe nanorods have been prepared for 5-hydroxymethylfurfural oxidation reaction. The doping of Ni facilitates the oxidation of Co2+ to high-valent CoO 2 to achieve efficient electrosynthesis of the valuable 2,5-furandicarboxylic acid. [Display omitted] • A crude nanorod structure CoNiTe was prepared by two-step hydrothermal reactions for HMFOR. • Ni doping modulates the electronic structure of Co and improves the electrocatalytic performance of CoNiTe. • The generation of high-valent cobalt is the key for excellent HMFOR. Replacing the anodic oxygen evolution reaction (OER) in water splitting with 5-hydroxymethylfurfural oxidation reaction (HMFOR) can not only reduce the energy required for hydrogen production but also yield the valuable chemical 2,5-furandicarboxylic acid (FDCA). Co-based catalysts are known to be efficient for HMFOR, with high-valent Co being recognized as the main active component. However, efficiently promoting the oxidation of Co2+ to produce high-valent reactive species remains a challenge. In this study, Ni-doped CoTe (CoNiTe) nanorods were prepared as efficient catalysts for HMFOR, achieving a high HMFOR current density of 65.3 mA cm−2 at 1.50 V. Even after undergoing five successive electrolysis processes, the Faradaic efficiency (FE) remained at approximately 90.7 %, showing robust electrochemical durability. Mechanistic studies indicated that Ni doping changes the electronic configuration of Co, enhancing its charge transfer rate and facilitating the oxidation of Co2+ to high-valent CoO 2 species. This work reveals the effect of Ni doping on the reconfiguration of the active phase during HMFOR. [ABSTRACT FROM AUTHOR]

Overall urea–water electrolysis has the potential to be employed in the purification of urea-containing wastewater and the production of hydrogen. However, the lack of cost-effective catalysts currently presents a significant obstacle to the further development of this technology. Through a simple template-directed selenium reaction in a novel type of highly active solution, an interface engineering strategy was designed to synthesize hollow CuSe nanocubes as an efficient bifunctional catalyst. The unique hollow CuSe nanocubes exhibit significant catalytic efficiency because of their larger electrolyte contact area and faster ion transport. In 1 M KOH with a 0.5 M urea electrolyte, CuSe/NF required an overpotential of 199 mV for HER and a potential of 1.38 V for UOR to achieve a current density of 10 mA cm−2. It can work stably for 24 h without significant degradation of activity at 10 mA cm−2, showing excellent durability and excellent stability. For overall urea–water electrolysis, it exhibits a remarkable activity with a low cell voltage of 1.61 V at 10 mA cm−2. Consequently, the design strategy of this unique hollow-structured CuSe provides a new insight to improve electrocatalytic performance and stability. [ABSTRACT FROM AUTHOR]

Low efficiency of photogenerated electron–hole separation has been a challenge for organic conjugated polymer photocatalysts. Our preceding studies have revealed that polymers containing B←N coordination bonds can form a localized built-in electric field that effectively promotes photogenerated charge separation. However, B←N coordination units are still scarce and require more examples to find regularities in their structural design. The systematic development and testing of B←N coordination units is necessary for the efficient development of subsequent polymers containing B←N coordination bonds. In this work, three conjugated polymers containing B←N coordination bonds, PBN–Ni, PBP–Ni, and PBS–Ni, were synthesized by changing the substituents of the boron atoms and introducing narrow-band thiophene units to form conjugate and energy band gradients. The energy band modulation and localized built-in electric field construction were both achieved as planned, while the bandgap and photogenerated charge transport capabilities caused performance discrepancies. The experimental results showed that PBN–Ni had a better photocatalytic hydrogen evolution (HER) performance, reaching 104.6 μmol h−1 (λ > 420 nm). The optimal optical absorption edge of PBS–Ni was up to 643 nm, but the HER was lower, at 33.2 μmol h−1 (λ > 420 nm, 1% Pt). PBP–Ni optimized some of the optical absorption efficiencies (511 nm) while ensuring the HER activity (96.6 μmol h−1, λ > 420 nm). This work tentatively explores the characterization of the B←N coordination bond-containing base units serving as photocatalysts and provides the basic model experience and data reference for the subsequent expansion of B←N coordination bond-containing units and the development of B←N coordination bond-containing copolymer systems. [ABSTRACT FROM AUTHOR]

This report addresses the synthesis, characterisation, and photoelectrochemical performances of α-Fe2O3 nanorods decorated with g-C3N4. Photoanode composites were fabricated in a two-step procedure in which fluorine-doped tin oxide (FTO) glass was coated with α-Fe2O3 nanorods via a hydrothermal method, followed by incorporation of g-C3N4via a wet-impregnation method. In particular, the study investigates the effects of precursors of g-C3N4 (urea, dicyandiamide, and melamine) on the photoelectrochemical properties of the prepared α-Fe2O3/g-C3N4 films. The films were thoroughly analysed by means of X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared (FTIR) spectroscopy, and UV-vis spectrometry. The highest photoelectrochemical output of the nanorod composite films was achieved with the use of g-C3N4 synthesized from urea, generating 15.3 μA cm−2 of photocurrent density as a result of better charge transfer driven by the formation of a semiconductor heterojunction. This is a staggering 12-fold improvement compared to the unmodified hematite nanorods which managed to only produce 1.2 μA cm−2 of photocurrent density. The merits of g-C3N4 prepared from urea as the best semiconductor couple for α-Fe2O3 are driven by its unique crystallinity and morphology with significantly larger surface area than g-C3N4 prepared from other precursors. The addition of glycerol as a sacrificial agent further improves the photocurrent to ca. 24 μA cm−2. The findings in this study show the potential of α-Fe2O3/g-C3N4 composites for sustainable photoelectrochemical hydrogen production. [ABSTRACT FROM AUTHOR]

In this study, a novel NiO/Co 3 O 4 /KNbO 3 heterostructured electrocatalyst with NiO and Co 3 O 4 particles coupled on KNbO 3 cubes was constructed using simple sol–gel and calcination processes. The formation of multiple interfaces between NiO, Co 3 O 4 , and KNbO 3 in the heterostructure contributed to a synergistic effect, adjusted the electronic structure, and generated abundant active sites at the interfaces. As a result, the NiO/Co 3 O 4 /KNbO 3 electrocatalyst exhibited remarkable urea electrolysis performance, including a low potential of 1.67 V at 100 mA cm−2 and a small Tafel slope of 29 mV dec−1. Furthermore, the change in the overpotential was negligible even after a rigorous stability test of 3000 cycles, highlighting its exceptional durability and reliability. This study provides a novel structural engineering strategy for achieving efficient hydrogen production and purification from urea-containing wastewater. [ABSTRACT FROM AUTHOR]

Conjunction of 'n' and 'p'-type materials have gained considerable attention for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) as potential substitutions to noble metal based nanomaterials. Current work has been designed to synthesize mixed-phase nanocomposite (NC) based on copper (CuO) and zinc oxide (ZnO) nanowires (NWs) and reduced graphene oxide (rGO). A facile chemical reduction method was used for the preparation of NWs, rGO were prepared using modified Hummer's method and lastly CuO/ZnO NWs were grafted on rGO to fabricate NC (CuO/ZnO@rGO) by wet-chemical approach. Characterization techniques were employed to confirm the formation as well as different morphological features of NC. Noticeable D and G bands in Raman spectrum confirmed the formation of NC and EDAX confirmed the presence of C, O, Zn and Cu. XRD analysis has confirmed hexagonal wurtzite structure of NC with a crystallite size of 10.1392 nm. Synthesized material was then investigated for OER and HER in an alkaline medium. As electrocatalyst, NC exhibited overpotential (OP) of 1.678 V to accomplish 10 mA/cm−2 current density (J) in OER and −358 mV (10 mA/cm−2) for HER respectively. Tafel curves of CuO/ZnO@rGO in OER (42 mV dec−1) and HER (270 mV dec−1) were found similar enough to others studies. Proliferated electrochemical activities are responsible for such a lower OP and Tafel slope values that may be due to electronic couplings of copper and zinc, or the homogenous distribution of both the metal oxides which gives polydispersity in their structure as confirmed by SEM images. Promising results of the current study indicated high-performance of synthesized electrocatalyst. Further studies can be designed to evaluate the efficiency of different combinations of noble/non-noble metals or metal oxides with rGO as potential candidate for electrochemical reactions. [ABSTRACT FROM AUTHOR]

The development of novel metal–organic frameworks (MOFs) as efficient photocatalysts for hydrogen peroxide production from water and oxygen is particularly interesting, yet remains a challenge. Herein, we have prepared four cyclic trinuclear units (CTUs) based MOFs, exhibiting good light absorption ability and suitable band gaps for photosynthesis of H2O2. However, Cu‐CTU‐based MOFs are not able to photocatalyzed the formation of H2O2, while the alteration of metal nodes from Cu‐CTU to Ag‐CTU dramatically enhances the photocatalytic performance for H2O2 production and the production rates can reach as high as 17476 μmol g−1 h−1 with an apparent quantum yield of 4.72 %, at 420 nm, which is much higher than most reported MOFs. The photocatalytic mechanism is comprehensively studied by combining the isotope labeling experiments and DFT calculation. This study provides new insights into the preparation of MOF photocatalysts with high activity for H2O2 production through molecular engineering. [ABSTRACT FROM AUTHOR]

A thermodynamic analysis was performed for the production of synthesis gas and hydrogen gas from steam reforming of propionic acid, one of the constituents of the bio-oil, using ASPEN Plus v8.8. The aim of the study was to perform a global analysis on steam reforming of propionic acid focusing on several parameters such as steam-to-propionic acid ratio, reaction temperature, addition of O 2 in the feed stream and presence of CaO as a CO 2 sorbent in the reaction environment. The results showed that higher amounts of steam/propionic acid ratio resulted in higher H 2 and CO 2 yields. It was also observed that high H 2 O/PA molar ratios led to reduced coke production as WGS reaction was favored with excess steam, causing CO in the reaction mixture to be consumed through the WGS reaction rather than the Boudouard reaction. Addition of O 2 in the reaction environment was observed to negatively affect yield of H 2. Yet, coke formation was deprived and increasing the O 2 amount in the feed stream decreased the energy required for the process. Furthermore, the presence of CaO enhanced H 2 yield and energy requirements of the process compared to conventional steam reforming process. 100 % yield of H 2 production with a heat generation of −83.4 MJ/kmol of PA and almost zero formation of CO 2 , CO, CH 4 and coke is achieved at 600 °C for sorption enhanced steam reforming of propionic acid. [Display omitted] • Maximum H 2 production is noted as 4.96 kmol/kmol of PA at 750 °C for H 2 O/PA = 4. • O 2 /PA molar ratio significantly affect the heat requirement & coke deposition. • Process enthalpy changes from 38.5 to −49.5 & −83.4 MJ/kmol with higher CaO. • 100% H 2 yield is achieved for CaO = 3 kmol/h at 600 and 700 °C. [ABSTRACT FROM AUTHOR]

The current work introduces novel and low-cost AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes for the photoelectrochemical (PEC) water-splitting reaction. The photoanodes were fabricated by anodizing commercial galvanized grids(A@CGGs) in the sodium carbonate solution followed by deposition of Ag or Cu through a simple electroless substitution. Surface studies showed that AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes have a unique morphology including Ag nanospheres (AgNSs) and Cu worm-like nanorods (CuNRs) with huge surface area. The UV-VIS diffuse reflectance spectra (DRS) of AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes displayed the lower band gap energies of 2.4 eV, and 2.83 eV respectively, which compared to 3.91 eV for the A@CGGs, showing excellent photoanodic behavior for AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes. Investigations of photoelectrochemical water-splitting under visible light irradiation showed that the production amount of H 2 from AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes was about 18570 and 6895 μmol h−1 cm−2 respectively. Moreover, AgNSs-A@CGGs showed 15.27 and 5.0 times higher photoconversion efficiency than CGGs and A@CGGs respectively. In this study, the introduced photoanode grids are expected to be used as cheap and industrial photoanodes for PEC water-splitting and hydrogen gas production. [Display omitted] • Ag nanospheres and Cu worm-like nanorod structures were developed using electroless substitution. • AgNSs-A@CGGs and CuNRs-A@CGGs showed outstanding photoelectrochemical activity. • The extremely high surface area was a factor contributing to this excellent performance. • The fabricated AgNSs-A@CGGs exhibited favorable photoanodic stability in hydrogen production. [ABSTRACT FROM AUTHOR]

Hydrogen production is a vital development trend to improve the economics and penetration rate of offshore wind farms (OWFs), and distributed hydrogen production (DHP) is a preferred solution for deep and far sea OWFs without expensive submarine cables and offshore substations. The export pathway of OWF-DHP consists of collection pipelines, transmission pipelines, and offshore compressor stations. In this paper, mathematical programming is introduced to explore the export pathway planning problem of OWF-DHP. Firstly, the area of OWF is discretized into multiple grids with the center of the grids being the candidate locations of the offshore compressor station. Then, a binary integer quadratic programming problem is established to optimize both the offshore compressor station location and pipeline construction with different topologies. Further, the mathematical model is solved by the branch and cut algorithm integrated with the proposed dimension reduction methods. Finally, the effectiveness of the proposed export pathway planning approach is verified by the actual data of Baltic Eagle OWF in Germany, which would support the construction of the OWF-DHP project. [Display omitted] • Studying export pathway planning (EPP) for OWF-distributed hydrogen production. • Introducing mathematical programming to model EPP as a BIQP problem. • Proposing dimension reduction methods to accelerate BIQP problem solving. • Verifying the effectiveness of the EPP approach with the Baltic Eagle OWF case. • Conducting sensitivity analysis on transportation carrier and pipeline topology. [ABSTRACT FROM AUTHOR]

Hydrogen production through electrocatalytic water splitting or urea splitting has been considered one of the most fascinating methods to relieve the energy pressure. In this paper, the effects of Zr introduction on formation of NiFe 2 O 4 and catalytic activity are studied. Using oxygen evolution and urea oxidation as concerned reactions, the effects of different dosage on the catalytic performance of the materials were performed. It was found that the Zr–NiFe LDH@NiFe 2 O 4 /NF-1 material exhibited superior water oxidation properties (overpotential of 290 mV @100 mA cm−2). For urea oxidation reaction, the catalytic performance of this NiFe LDH material is better at low current density. However, at high current densities, this Zr–NiFe LDH@NiFe 2 O 4 /NF-1 electrode exhibits better electrochemistry performance. It is proved that the oxidation of water also contributes a part of the activity under large current. Density functional theory also suggests that the NiFe 2 O 4 material is favorable for water adsorption. This work will provide novel opinion for the development of environmentally friendly and low cost materials. It was found that the Zr–NiFe LDH@NiFe 2 O 4 /NF-1 material exhibited superior water oxidation properties (overpotential of 290 mV @100 mA cm−2). [Display omitted] • The formation of this NiFe LDH and NiFe 2 O 4 material can be induced by modulating the content of Zr. • The Zr–NiFe LDH@NiFe 2 O 4 presents a improved activity with small overpotentials of 290 mV for water oxidation. • The increase of performance is ascribed to the accelerated charge transfer and promoted electrolyte transfer. [ABSTRACT FROM AUTHOR]

The polyphenylene sulfide (PPS) mesh-based polysulfone (PSF)-zirconia (ZrO 2) composite diaphragm represents a new type of high-performance diaphragm for alkaline water electrolysis hydrogen production, offering low area resistance and high chemical stability. In this study, composite diaphragms with excellent performance are prepared using preheated compression molding, phase inversion precipitation, and vacuum stirring degassing techniques. The comprehensive performance of the prepared diaphragm is compared to that of the commercial Zirfon® diaphragm. The results indicate that the prepared composite diaphragm, with a thickness of 140 μm, exhibits excellent performance. Compared to the Zirfon® UTP 220 diaphragm, the ultra-thin composite diaphragm demonstrates a reduction in area resistance from 0.19 Ω cm2 to 0.1 Ω cm2, an increase in bubble point pressure from 2.31 bar to 2.46 bar, and a voltage of 1.84 V at 1000 mA cm−2. The incorporation of the PPS mesh resulted in a substantial improvement in tensile strength. The application of an ultra-thin composite diaphragm based on PPS mesh can significantly enhance the efficiency of hydrogen production via alkaline water electrolysis. [Display omitted] • Hot-pressing, phase inversion, and vacuum stirring degassing techniques are adopted. • Sponge pore structure improves the bubble point pressure of composite diaphragms. • Ultra-thin composite diaphragm with low area resistance and cell voltage. • It can work continuously and stably in a high-intensity electrolysis environment. [ABSTRACT FROM AUTHOR]

Plastic waste entering the environment through landfilling or improper disposal poses substantial risks to ecosystems and human health. Photoreforming is emerging as a clean photocatalytic technology that degrades plastic waste to organic compounds while simultaneously producing hydrogen fuel. This study introduces high-pressure torsion (HPT), a severe plastic deformation (SPD) method, as an innovative technique to enhance the photoreforming of polypropylene (PP) plastic mixed with a brookite TiO 2 photocatalyst. Hydrogen production systematically increases with the number of HPT turns, accompanied by the formation of valuable small organic molecules. The enhancement in photocatalytic activity is attributed to strain-induced defect formation in both catalysts and plastics, as well as the creation of catalyst/plastic interphases that enhance charge carrier transport between inorganic and organic phases. These findings reveal a new functional application for SPD in energy conversion and sustainability. • High-pressure torsion (HPT) is used for the photodegradation of polypropylene plastic wastes. • Brookite TiO 2 is employed as a photocatalyst for the photodegradation. • Hydrogen production from plastic degradation increased with HPT processing. • This increase is due to strain-induced defects and catalyst/plastic interphase formation. [ABSTRACT FROM AUTHOR]

This study investigates carbon-nitrogen thin films as active materials in photocatalytic methanol reforming, addressing the need for eco-friendly fuels with minimal waste and non-metallic photocatalysts. Additionally, it explores the synthesis of these materials using plasma-enhanced chemical vapor deposition (PECVD) from acrylonitrile or acetonitrile. This area has limited prior attention in carbon-nitrogen materials synthesis, particularly with subsequent application in methanol reforming offering potential advancements in clean energy production. The aim is to develop effective, environmentally friendly sources of hydrogen, where photocatalysts play a crucial role. The studies involved also characterization for morphology, and chemical structure. The results confirmed the activity in hydrogen production through methanol reforming, achieving a promising rate of 82 ± 6 μmol h−1 cm−2. [Display omitted] • Facile preparation of carbon-nitrogen films by cold plasma. • Non-metallic carbon-nitrogen catalysts for hydrogen production. • Hydrogen production rate of 32–82 μmol h−1 cm−2 over studied materials. [ABSTRACT FROM AUTHOR]

Hydrogen energy produced through photocatalytic water splitting is widely recognized as a viable solution to the depletion of non-renewable energy resources and ecological contamination concerns. This work designed and synthesized the MOF-derived hollow octahedral Co x P/MOF-801 p-n heterojunction photocatalyst. According to the result of hydrogen production test, the hydrogen production amount of Co x P/MOF-801-2 could reach 25.31 mmol g−1 under light irradiation for 5 h. The hollow octahedral structure and p-n heterojunction of the photocatalyst helped to enhance the light trapping ability and promote carrier transfer, resulting in improved performance of photocatalytic hydrogen production. To sum up, the design of hollow octahedral Co x P/MOF-801 photocatalyst effectively improved the photocatalytic hydrogen production performance. [Display omitted] • MOF-derived hollow octahedral MOF-801 was synthesized and modified with Co x P nanoparticles. • The p-n heterojunction inhibited the recombination of electrons and holes. • The Co x P/MOF-801 exhibited excellent hydrogen production activity and stability. [ABSTRACT FROM AUTHOR]

This review covers the methods of hydrogen production through water electrolysis, encountered problems, used catalysts, methods of preparing these catalysts, and especially the method of electrode modification using the electrophoretic deposition technique. The methods of hydrogen production mechanism, electrode and electrocatalyst structures, and electrode modification techniques are classified based on types of the electrolyzers namely Alkaline Water Electrolysis (AEL), Anion Exchange Membrane (AEM) Water Electrolysis, Proton Exchange Membrane Electrolysis (PEMEL) and Solid Oxide Electrolysis (SOEL). The mechanisms of hydrogen evolution and oxygen evolution reactions, which are crucial in hydrogen production, have been provided in all types of electrolyzers. The parameters influencing these reactions on the anode and cathode electrodes have been discussed. This review summarizes and compares important parameters that show the catalyst's performance in detail. The fundamental principles of the electrophoretic deposition technique have been explained, and examples of electrocatalysts prepared using this technique have been provided. • Green hydrogen production technologies are introduced based on water electrolyzers. • Electrocatalysts used in water electrolyzers are discussed. • Enhanced electrode modification techniques are introduced and compared. • Electrophoretic deposition of catalysts on the electrodes of water electrolyzers are reviewed in detail. [ABSTRACT FROM AUTHOR]

This study presents a novel microwave-assisted dry reforming of methane (MW-DRM) method, significantly enhancing syngas (H 2 +CO) production at a lower temperature of 400 °C. Compared to conventional heating dry reforming of methane (CH-DRM) processes, MW-DRM achieves higher conversion rates of CH 4 (84.6%) and CO 2 (85.7%) at a lower temperature of 500 °C, significantly reducing energy consumption. The CsRu/CeO 2 catalyst exhibited excellent stability under microwave heating, maintaining high conversion rates and selectivity for 8 h. Detailed characterization using XRD, BET surface analysis, Raman spectroscopy, TEM, and CO chemisorption revealed insights into the structural changes of the catalyst, highlighting the selective impact of microwave heating on the catalyst structure. This study provides a promising approach for sustainable and cost-effective syngas and hydrogen production, aligning with greenhouse gas reduction goals. [Display omitted] • Dry reforming of methane is conducted under microwave conditions. • Microwave-enhanced DRM demonstrated high efficiency. • Compared to CH-DRM, MW-DRM achieves the same activity at 200 °C lower. • CsRu/CeO 2 catalyst demonstrated high stability in DRM. [ABSTRACT FROM AUTHOR]

The key to designing energy-efficient hydrogen production systems lies in the development of highly catalytic, low-cost non-precious metal catalysts, along with the substitution of high-energy-consuming oxygen evolution reactions with reactions involving easily oxidizable small molecules at the anode. In this paper, molybdates (NiMoO 4 and CoMoO 4) that grow on nickel foam are treated with vulcanization and nitriding methods, and Mo doped Ni 3 S 2 (Mo–Ni 3 S 2) and N doped CoMoO 4 (N–CoMoO 4) are prepared, respectively. Mo–Ni 3 S 2 exhibits excellent UOR activity requiring only 1.335 V to drive 100 mA cm−2. It is found that Mo–Ni 3 S 2 participated in both of the decomposition of urea (15.4 %) to form NH 3 and the oxidation reaction of urea (84.6 %) to form N 2 to keep the anodic reaction in the low potential range, avoiding the oxidation of nickel sites in the catalyst to form NiOOH. In addition, N–CoMoO 4 catalyst exhibits excellent hydrogen evolution reaction (HER) activity requiring only 67 mV to drive 100 mA cm−2. Finally, the catalysts prepared by molybdate are used to construct urea oxidation electrolytic system. The Mo–Ni 3 S 2 (+) || N–CoMoO 4 (−) urea oxidation-assisted water splitting system requires only 1.47 V to achieve 100 mA cm−2, which is a voltage reduction of 180 mV compared to conventional water electrolysis systems. The system realizes high energy efficiency hydrogen production and urea wastewater purification. This work provides insights into the design of low-energy-consuming hydrogen production systems. [Display omitted] • The catalysts prepared by molybdate exhibit efficient UOR and HER activity. • Mo–Ni 3 S 2 follows a new UOR mechanism of urea decomposition and urea oxidation. • The Mo–Ni 3 S 2 (+) || N–CoMoO 4 (−) system requires only 1.47 V to afford 100 mA cm−2. • We couple UOR and HER to construct an energy-saving hydrogen production system. [ABSTRACT FROM AUTHOR]

This study demonstrated a machine learning approach to predict the photocatalytic properties of graphitic carbon nitride (g-C 3 N 4) depending on its synthesis parameters to enhance photocatalytic hydrogen production. In connection with the task, a database was experimentally formed to prepare g-C 3 N 4 samples by heat treatment of nitrogen-containing precursors in air at a temperature of 450–600 °C with varying time and heating rates of the synthesis. Physicochemical analyses characterized the materials, including X-ray diffraction and low-temperature nitrogen adsorption. Several machine learning algorithms were used to process the obtained data, which showed a high-efficiency R2 above 0.9. Hyperparameters were optimized for each model using different preprocessing methods. In addition, the importance of features for selecting the most effective sample was assessed. For convenience, a web application was created with the ability to expand the database to work with machine learning models. [Display omitted] • Database on g-C 3 N 4 modification and preparation with synthesis parameter variations. • Machine learning (ML) predicts g-C 3 N 4 properties for enhanced hydrogen production. • Web app with ML models and expanding database. • ML algorithms achieved high R2 efficiency above 0.9. [ABSTRACT FROM AUTHOR]

In this study we evaluated three binary salt mixtures of 50 wt% potassium bromide and 50 wt% sodium chloride, manganese chloride, or magnesium chloride for methane pyrolysis in a bubble column reactor configuration. Initial results confirm preferential mixtures of reciprocal salts that tune salt ionicity. This study focusses on the interactions of these binary salt mixtures with 5 wt% suspensions of 2-μm 2H-MoS 2 with a 100 mm bubble path at 800 and 850 oC. Magnesium chloride and potassium bromide show a favourable enhancement with MoS 2 , with an apparent activation energy of 251 kJ mol−1 (salt mixture) decreasing to 96 kJ mol−1 (slurry mixture). Assessing the results indicates that MgCl 2 -KBr melts promote increased contact with MoS 2 relative to NaCl-KBr and MnCl 2 -KBr, and this in turn improves hydrogen yield. Further investigation of slurry system through deuterium-methane exchange confirms molybdenum disulfide promotes methane decomposition to protium, hydrogen, methyl radical, and methylene, preferentially intensified by magnesium mixtures. Additional reaction steps vary depending on salt selection. At 850 oC, the salt effect is significant, leading to an inverse relationship between net increase of side products in the slurries and salt activity. In contrast, at 800 oC, the salt effect is small, and activity is dictated by the MoS 2 suspension. [Display omitted] • Mechanistic explanation of reaction step in MoS 2 molten salt slurry systems. • Kinetics of a range of MoS 2 molten salt slurry systems. • Description of 3 novel slurry systems for methane pyrolysis. [ABSTRACT FROM AUTHOR]

In recent years, there has been increasing focus on two-dimensional (2D) materials, especially those derived from chalcogenides, due to their distinctive electrical and mechanical properties, which are crucial for numerous applications, particularly in the field of photocatalysis. Recent studies have concentrated on 2D Janus structures, investigating architectures where layers of Group-13 elements (Ga, In, and Tl) are interleaved between layers of chalcogen atoms (S, Se, and Te). Our research specifically examines the effects of swapping the positions of Group-13 and chalcogen atoms within Tl 2 S 2 and Janus XTlS 2 (X = Al, Ga, In), emphasizing their potential as catalysts for hydrogen production through photocatalysis. Detailed analyses of the structural, optical, and electronic properties of these nanosheets were provided to elucidate their role in enhancing photocatalytic efficiency. The findings reveal the presence of covalent bonding between the two inner layers in all the compounds studied. Band structure analysis indicates that these systems are semiconductors with band gaps ranging from E g = 0.34 eV for GaTlS(1) to Eg = 1.84 eV for TlS(1). Moreover, all compounds exhibit their highest absorption peaks in the ultraviolet (UV) range, making them efficient absorbers of sunlight for potential use in photovoltaic and photocatalytic applications. Notably, these systems demonstrate low rates of charge carrier recombination due to the presence of a built-in electric field (in Janus structures) or their indirect band gap character. Additionally, except for ATlS(1), the compounds show promise as photocathodes for hydrogen production even through seawater splitting, pH = 8.3, with an absolute value of the Gibbs free energy change | Δ G | < 1. 5 eV. In contrast, InTlS(1) emerges as an exceptionally promising material for applications in highly acidic environments, exhibiting a Δ G of about −0.53 eV. [Display omitted] • DFT study of 2D material-based photoelectrodes for water splitting. • Tl 2 S 2 and Janus XTlS 2 (X = Al, Ga, In) 2D materials with novel atomic arrangements. • Nanosheets show potential for hydrogen production at neutral pH. • GaTlS(1) demonstrates spontaneous seawater splitting. • InTlS(1) effective in acidic water photoelectrolysis. [ABSTRACT FROM AUTHOR]

Green hydrogen or renewable hydrogen is promising cause it has no carbon emissions in production process, which is water electrolysis with electricity from renewables. Although grids can ensure stable and enough electricity supply, it is difficult to determine whether the grid electricity for hydrogen production is from renewable sources. This article uses EU rules to identify green hydrogen produced by grid electricity and analyse the production. European grids are classified according to the calculated indexes regarding renewables penetration and electricity carbon emission intensity. The negative correlation between green hydrogen production and electricity prices in different time scales and geographical distribution is concluded. Using imported electricity can improve the potential and diversity of green hydrogen production. Nordic countries and Albania have the most potential of green hydrogen production using grid electricity. The results can be a reference for the electricity market on flexibility supply and the future green hydrogen market development. • Nordic countries and Albania have the most green hydrogen production by grid power. • Other bidding zones with lower electricity prices have more green hydrogen production. • Green hydrogen production is negative correlated with hourly electricity prices. • Using imported electricity can improve the production potential and diversity. • Green hydrogen production by grid power can provide flexibility to electricity market. [ABSTRACT FROM AUTHOR]

The transition to sustainable energy sources is a global imperative in the face of climate change and dwindling fossil fuel reserves. Hydrogen, as a clean and versatile energy carrier, has garnered significant attention as a potential solution. This paper provides a comprehensive overview of various electrolyzer types, their features, advantages, disadvantages, and future expectations in the context of sustainable energy generation. The article begins by outlining the fundamental principles of electrolysis, highlighting its potential to harness surplus renewable energy. Four main types of electrolyzers are discussed: alkaline electrolyzers, proton exchange membrane electrolyzers, anion exchange membrane electrolyzers, and solid oxide electrolyzers. Each type is explored in depth, with a focus on their unique operating principles, efficiency, scalability, and suitability for different applications. The paper further delves into recent advancements in electrolyzer technology, discussing emerging trends, improved catalysts, and innovative system designs aimed at enhancing efficiency and reducing costs. It also explores the role of policy support and research initiatives in accelerating the adoption of electrolysis for sustainable hydrogen production. • Water electrolyzer systems are one of the most promising technologies for green hydrogen production. • This review provides insights into the current state and future potential of water electrolysis technologies. • Challenges, advantages, and future directions of electrolyzer types are discussed. • Green hydrogen plays a crucial role in decarbonization efforts and offers a sustainable solution for future energy needs. [ABSTRACT FROM AUTHOR]

Reforming ammonia to hydrogen using engine exhaust waste heat is a promising technology to improve the combustion performance and reduce the exhaust emissions of ammonia-fueled engines. However, there are still a research gap between the laboratory-level catalytic reforming tests and the practical application in engine systems. In particular, there are urgent needs to further understanding the ammonia reforming characteristics and developing the simulaiton models for the engine system optimization. In this paper, we conducted the experiments of catalytic reforming NH 3 to H 2 to study the effects of the reaction temperature, gas hour space velocity (GHSV) and pressure on the thermo-catalytic decomposition characteristicsxin. The results indicate that both the ammonia catalytic conversion and reforming efficiency exhibit an increasing trend with the rise in reaction temperature, while these two parameters demonstrate a decreasing trend with the increase in GHSV and pressure. The rate of hydrogen production is directly proportional to temperature, GHSV, and reaction pressure. Conversely, the energy required per unit of hydrogen production decreases with temperature but increases with GHSV and reaction pressure. The energy flow analysis shows that increasing the reforming temperature increases the reforming losses, but the total calorific value of the reformate increases, which is expected to improve the overall efficiency of ammonia fueled engines and reduce the unburned ammonia emissions. Simulation results show that, the improved Temkin-Pyzhev global rate model can significantly improve the accuracy of the ammonia catalytic decomposition process prediction. [Display omitted] • A novel energy flow analysis method for thermo-catalytic reforming is presented. • A precise predictive model for thermo-catalytic characteristics is established. • The thermo-catalytic system has a system efficiency of up to 94%. • The thermo-catalytic system has a reforming efficiency of up to 112%. [ABSTRACT FROM AUTHOR]

This work reports a novel TiO2/g-C3N4 photoanode-based photocatalytic fuel cell (PFC) designed to convert chemical energy from simulated wastewater. The g-C3N4 modified TiO2 nanorod was successfully synthesized by a facile hydrothermal method. The results indicated that the maximum photocurrent density reached 2.44 mA cm-2 at 1.23 V vs. RHE by 1.167 g L-1 g-C3N4 loaded TiO2 composite. On the basis of analysis, the photoelectrochemical mechanism of the composite photoanode was proposed. This mainly demonstrated that the composite photoanode increases the electron donor density and boosts charge separation efficiency. In addition, the power density and hydrogen production of the proposed PFC were enhanced by 5.37 and 1.49 times compared to TiO2 photoanode-based PFC. To find the origins of the excellent performance of PFC, the influence of the organic compounds were investigated. The ESR measurement results indicated that the organic matter was captured by the photoexcited holes directly to facilitate the charge separation. The achieved power density and hydrogen production of 0.14 mW cm-2 and 21.60 μmol h-1 cm-2 were measured using RhB as the model pollutant, which was 2.42 and 1.23 times higher than the experiments with PBS electrolyte. This study proposed a novel PFC system converts the organic pollutant to the hydrogen and the electricity. [ABSTRACT FROM AUTHOR]

Degenerate strains of Clostridium acetobutylicum lack the ability to produce solvents and sporulate and remain in a permanent acidogenic state, allowing continuous hydrogen and organic acid production through anaerobic fermentation. Eichhornia crassipes, an invasive aquatic plant, emerges as a promising source of fermentable sugars for hydrogen production via anaerobic fermentation. In this study, a degenerated strain of Clostridium acetobutylicum was isolated and subsequently cultivated in the presence of a hydrolysate solution obtained from the alkaline pre-treatment and enzymatic hydrolysis of Eichhornia crassipes. The hydrolysate was mixed with a defined medium and served the dual purpose of providing essential nutrients and mitigating inhibitors, eliminating the need for an additional detoxification step. A pure defined culture medium served as a control. The extraction methods employed led to the release of low concentrations of inhibitors, reaching 0.1 g/L of furfural and 0.18 g/L of HMF. Kinetic characterization revealed that in the presence of Eichhornia crassipes hydrolysate, the degenerate strain exhibited lower specific growth rates ranging from 0.114 to 0.156 h−1, compared with the control medium which ranged from 0.131 to 0.179 h−1. This was accompanied by lower yields, ranging from 0.115 to 0.167 gDCW/g in the presence of hydrolysate versus 0.178 to 0.190 gDCW/g in the control medium, and diminished butyric acid production of 1.318 to 2.932 g/L in the presence of hydrolysate versus 1.749 to 3.471 g/L in control cultures. Despite reduced growth, high biohydrogen volumetric productivity was achieved, reaching 7.3 L/L·d, along with a significant yield of 2.642 mol of hydrogen per mole of glucose consumed. This represents 66.05% of the maximum stoichiometric yield calculated when acetic acid is the sole byproduct. Apparently, the presence of low concentrations of furfural and HMF released during the pre-treatment of Eichhornia crassipes not only negatively affects growth capacity but also diminishes butyric acid production, favoring biohydrogen production. [ABSTRACT FROM AUTHOR]

The production of hydrogen through urea electrolysis exhibits many advantages such as low consumption, cost-effectiveness, high efficiency, and environmental friendliness. Here, a layered triple hydroxide (BiCoAl-LTH) was grown in situ on nickel foam (NF) to prepare a self-supported electrode. The BiCoAl-LTH/NF electrode exhibits a unique two-dimensional array structure. Since Al is easily etched in a strong alkaline solution, a large number of oxygen vacancies are generated, which is conducive to improving the conductivity of BiCoAl-LTH/NF catalyst and thereby enhancing its urea oxygen reaction (UOR) activity. The BiCoAl-LTH/NF can achieve a current density of 100 mA/cm2 at an overpotential of 198 mV in UOR process. The BiCoAl-LTH/NF was used as both the anode and cathode to construct a urea electrolysis system. A current density of 100 mA/cm2 can be achieved with only a cell voltage of 1.65 V. Compared to conventional water electrolysis with the oxygen evolution reaction at the anode, the BiCoAl-LTH/NF catalyst can save 40% of energy in urea electrolysis for hydrogen production. [ABSTRACT FROM AUTHOR]

Preparation and study of FeOOH modified Co 9 S 8 composites were successful. The catalysts have abundant non-homogeneous interfaces between FeOOH and Co 9 S 8 nanosheets, which optimize the coordination environments of Fe and Co sites through the redistribution of interfacial charges. This results in appropriate chemisorption strength of oxygenated intermediates, leading to accelerated reaction kinetics, abundant active sites, and good OER properties. [Display omitted] • The FeOOH/Co 9 S 8 composites electrocatalyst was developed. • The redistribution of interface charges optimizes the coordination environment of Fe and Co sites. • Appropriate chemisorption strength of oxygenated intermediates. Efficient oxygen evolution reaction (OER) is vital for water electrolysis and advanced hydrogen energy production. However, the sluggish kinetics of this reaction require significant overpotentials, leading to high energy consumption. Therefore, developing OER electrocatalysts with exceptional performance and long-term durability is crucial for enhancing the energy efficiency and cost-effectiveness of the hydrogen production process. In this research, novel FeOOH/Co 9 S 8 catalysts were prepared through a two-step hydrothermal reaction followed by one-step electrodeposition on nickel foam for an alkaline OER. The as-obtained catalysts possessed abundant non-homogeneous interfaces between FeOOH and Co 9 S 8 nanosheets, conducive to optimized coordination environments of Fe and Co sites by redistributing interfacial charges. This synergy strengthened the chemisorption of oxygenated intermediates, leading to accelerated reaction kinetics, abundant active sites, and enhanced OER performance. The optimized electrocatalyst FeOOH/Co 9 S 8 -15 achieved a current density of 10 mA cm-2 at an overpotential of 248 mV and good stability for over 140 h. This study presents a novel approach for producing compelling and durable alkaline dielectric OER electrocatalysts, which will be helpful in the future manufacturing of advanced energy devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • A unique 1D/2D hierarchical structure is successfully constructed. • The catalyst exhibits superhydrophilicity and superaerophobicity. • The as-prepared catalyst displays outstanding performance for HER and UOR. Utilizing the thermodynamically favorable urea oxidation reaction instead of the anodic oxygen precipitation reaction is an alternative pathway for the energy-saving hydrogen production. Therefore, it is significant to explore advanced electrocatalysts for both HER and UOR. In this work, a dendritic heteroarchitectures of 2D CoMoO 4 nanosheets deposited on 1D CoP nanoneedles (CoP/CoMoO 4 -CC) was fabricated as bifunctional electrocatalyst. 1D CoP nanostructure with fast charge transport pathways and 2D CoMoO 4 nanostructure with large specific surface area and short paths for electron/mass transport. The unique morphology endows the superhydrophilic and superaerophobic properties, allowing for the rapid contact with the reactants and rapid removal of surface-generated gases. As a result, the CoP/CoMoO 4 -CC shows efficient bifunctional activity. This work offers a new avenue to rationally design bifunctional electrocatalysts for large-scale practical hydrogen production. [ABSTRACT FROM AUTHOR]

[Display omitted] Developing a high-activity and low-cost catalyst to reduce the anodic overpotential is essential for hydrogen production from water splitting. In this work, a hetero-structured Co 7 Fe 3 /Mo 2 C@C catalyst has been developed to efficiently catalyze oxygen evolution reaction (OER), the overpotential (ƞ 10) of Co 7 Fe 3 /Mo 2 C@C-catalyzed OER with current density of 10 mA/cm2 is about 254 mV, substantially lower than the counterparts of Co 7 Fe 3 @C-catalyzed OER (ƞ 10 , 308 mV) and Mo 2 C@C-catalyzed OER (ƞ 10 , 439 mV), close to that of OER catalyzed by commercial RuO 2. The mechanistic studies reveal that the distinct electron transfer across the Co 7 Fe 3 /Mo 2 C interface results in electron-deficient Co 7 Fe 3 , which has been identified as the highly active catalytic sites. Density functional theory (DFT) calculations manifest that Mo 2 C induces a distinct decrease in electron density on Co 7 Fe 3 and upgrades the d -band centers of Co and Fe in Co 7 Fe 3 towards Fermi energy level, thus substantially lowering the energy barrier of the rate-determining reaction step and conferring significantly improved OER activity on the Co 7 Fe 3 /Mo 2 C@C catalyst. [ABSTRACT FROM AUTHOR]

Electron transfer mechanism of C-Ni 5 P 4 /CdS under visible light irradiation. [Display omitted] The capacitance of a co-catalyst can be likened to a "double-edged sword". Α co-catalysts with high capacitance can store photoexcited electrons, thereby facilitating charge separation within the host catalyst. However, this property simultaneously restricts electron release. Both effects are enhanced with an increasing capacitance value, implying that excessively high capacitance can significantly hinder the photocatalytic hydrogen (H 2) production reaction. Herein, we have designed a metal-organic framework (MOF) -derived carbon-coated nickel phosphide (C-Ni 5 P 4) as the co-catalyst of cadmium sulfide (CdS). When C-Ni 5 P 4 and CdS are closely interconnected, electrons spontaneously migrate from CdS to C-Ni 5 P 4 under irradiation due to the higher work function (WF) of C-Ni 5 P 4 compared to CdS. Most importantly, although the WF of C-Ni 5 P 4 is 0.1 eV lower than that of Ni 5 P 4 , its specific capacitance (1.2 mF/cm2) is also lower than that of Ni 5 P 4 (1.3 mF/cm2). This difference dramatically promotes electron release. Thereby exerting a strong positive effect on capacitance catalysis. Therefore, 7% C-Ni 5 P 4 /CdS exhibits exceptional cyclic stability and has a remarkably high activity level of 12283 μmol/h/g and 3.8 times as many as 3.0 %Ni 5 P 4 /CdS. This study provides a theoretical basis for the advancement of photocatalysts with high efficiency in H 2 production and is expected to be applied in other fields of photocatalysis. [ABSTRACT FROM AUTHOR]

The photogenerated electrons in the CB of MCN-3 tend to transfer to the VB of InS under the combined action of the internal electric field, band edge bending and coulomb interaction. The electrons enriched the CB of InS reduce O 2 to form O 2 –, while the holes located at the VB of MCN-3 oxidize the alcohol to produce protons (H+), ultimately generating further H 2 O 2. S-scheme heterostructure encourages the spatial separation of electrons and holes and prolongs the lifespan of photoexcited electrons, augmenting the photocatalytic activity of MSCN-5 composite. [Display omitted] • A novel potassium ion-doped g-C 3 N 5 /In 2 S 3 composite has been synthesized for the first time. • Hydrogen peroxide over g-C 3 N 5 /In 2 S 3 reached 3890 μmol g−1h−1, 10.4 times than over pure g-C 3 N 5. • The molten salt modification increases the specific surface area of g-C 3 N 5. • Introduction of In 2 S 3 further increases specific surface area and light absorption capacity of composite. • S-scheme heterojunction formation between K+/g-C 3 N 5 and In 2 S 3 inhibits the electron/hole complexation. Graphitic phase carbon nitride (g-C 3 N 5), as a novel n -type metal-free material, is employed as a visible light-receptive catalyst because of its narrow band gap and abundant nitrogen. To overcome the low carrier mobility efficiency of g-C 3 N 5 , its modification by K ions was adopted. In addition, In 2 S 3 was selected to couple with modified g-C 3 N 5 to overcome the recombination of photogenerated e−/h+. As a novel photocatalytic material, it was proven to possess a high visible light absorption capacity and a strong H 2 O 2 production ability (up to 3.89 mmol⋅L-1 in 2 h). Moreover, a S-scheme heterojunction structure was successfully constructed between the two materials, which was tested and confirmed to be successful in raising the photogenerated e−/h+ separation efficiency. Ultimately, the primary processes of photocatalytic H 2 O 2 production were summarized by superoxide radical and rotating disc electron measurements. This research provides a fresh perspective for the synthesis of C 3 N 5 -based S-scheme heterojunction photocatalysts for producing H 2 O 2. [ABSTRACT FROM AUTHOR]

In this paper, we report on a photocatalytic water-splitting device comprising a TiO2 photoanode combined with Se/TiO2heterojunction photovoltaic (PV) devices. A Se/TiO2PV device can supply its photo-induced open circuit voltage to a TiO2-Pt photoelectrochemical cell (PEC) in order to assist photoelectrolysis for H2 and O2 gas generation without external electrical sources. The open circuit voltage was increased from 0.65 V to approximately 3.2 V by the serial connection of five Se/TiO2PV devices. Hydrogen and oxygen bubbles were successfully generated by only light illumination without using any wired external voltage source. A photoanode with sol–gel derived porous TiO2films was used to increase the surface area to attain a stronger photocatalytic reaction. Microdot patterns of Pt were formed as the co-catalyst on a TiO2photoanode to suppress the back reaction of the photogenerated carrier. A Pt anode was formed on a glass substrate. Parameters related to the photocatalytic reaction, such as atmospheric pressure, the type of chemical additive, and the area ratio of Pt co-catalyst patterns to the surface area of the TiO2photoanode, were varied to generate a larger gas volume with the water-splitting device. [ABSTRACT FROM AUTHOR]

The paper presents research results of the synthesis, phase composition, and structure of products obtained by highly exothermic reactions between Ti and C10H8O4 mixture components, depending on the plastic waste concentration and Ti powder dispersiveness, density of initial samples, and synthesis medium. The dependence of the phase composition and structure of the synthesis products on the concentration of the polymer (plastic) component in the initial Ti -PET (C10H8O4) system was found. When the plastic waste content is 20 wt% to 25 wt %, synthesis products contain TiC0.5O0.5-TiC0.6-0.75 particle agglomerates. Further growth in the polyethylene terephthalate content from 30 wt% to 45 wt% leads to the formation of synthesis products consisting of titanium carbide (TiC0.6-1.0). The gaseous byproduct composition of the exothermic reaction is investigated for the Ti--C10H8O4 mixture composition. It is found that the gaseous by-product mostly contains hydrogen and carbon monoxide as well as impurities of different hydrocarbons (methane, acetylene, ethane, ethene) and carbon dioxide. The maximum adiabatic temperature of the gas combustion temperature is 2080 °C, which demonstrates the possibility of using gas as a fuel for energy generation devices. Based on the data obtained, it is possible to create a basis for a new plastic waste technology to fabricate carbide-containing materials. [ABSTRACT FROM AUTHOR]

Novel and economic supports were prepared to facilitate the NiO‐reducibility and enrich the hydrogen production from the catalytic conversion of methane. Mixed (CaTi)‐oxides of CaO %=10, 20, and 30 were synthesized by direct compositing of CaCO3 and one‐pot synthesized (TiO2)‐nanoparticles. The developed nanostructures were characterized by a high‐resolution transmission electron microscope, X‐ray diffraction (XRD), temperature programmed reduction (TPR), and N2 adsorption‐desorption measurements. Practically, (Ni@30 % CaTiO3) the catalyst of cubic morphology, achieved a high hydrogen production ratio of 62.2 %. The incorporation of CaO to TiO2 hindered the formation of NiTiO3@NiCaTiO3 phases and facilitated the fast reduction of NiO‐phase to Ni (as revealed by temperature programmed reduction (TPR) and XRD. The formation of well‐ordered carbon nanotubes (CNTs) as valuable by‐products was also possible by these nanocomposites. The developed catalysts exhibited remarkable catalytic and structural stabilities. These results reflect the effective use of abundant CaO inorganic salt to enrich the H2 production by (CaTiO3) supports for potential and green energy production. [ABSTRACT FROM AUTHOR]

Due to the high cost of ultra‐pure water supply and the mismatch between water sources and renewable energy distribution, the large‐scale production of green hydrogen through seawater electrolysis has generated significant interest. This presents an attractive potential technology within the framework of carbon‐neutral energy production. However, owing to the complex composition of seawater, particularly the competitive oxidation reactions and corrosion issues involving Cl−, seawater electrolysis has suffered from low selectivity and poor stability in oxygen evolution reaction (OER), which severely impact the efficiency of hydrogen production and hinder the practical applications. To further promote in‐depth research and practical applications of seawater electrolysis, this review introduces the principles, key advantages, and challenges of seawater electrolysis. Specifically, the design strategies are categorized for highly active OER electrocatalysts for seawater electrolysis, including catalyst design, design of chemical reaction systems, and other special process design. To ensure long‐term operational stability of seawater electrolysis, various strategies such as employing self‐supporting materials, surface protection strategies, and electrolyzer design, are discussed. Finally, current challenges and future prospects for the industrialization of seawater electrolysis are proposed and discussed. It is expected that this review provides new insights for large‐scale seawater‐based hydrogen production in the future. [ABSTRACT FROM AUTHOR]

The energy transition from fossil fuel-based to renewable energy is a global agenda. At present, a major concern in the green hydrogen economy is the demand for clean fuels and non-noble materials to produce hydrogen through water splitting. Researchers are focusing on addressing this concern with the help of the development of appropriate non-noble-based photo-/electrocatalytic materials. A new class of two-dimensional materials, MXenes, have recently shown tremendous potential for water splitting to produce H2 via a photoelectrochemical process. The unique properties of emerging 2D MXene materials, such as hydrophilic surface functionalities, higher surface-to-volume ratios, and inherent flexibility, present these materials as appropriate photo-/electrocatalytic materials. Unique value addition and innovative strategies such as the introduction of end-group modification, heterojunctions, and nanostructure engineering have shown the potential of MXene materials as emerging photo-/electrocatalysts for water splitting. When integrated with conventional noble metal catalysts, MXenebased catalysts demonstrated a lower overpotential for hydrogen and oxygen evolution reactions and a remarkable boost in performance for enhanced H2 production rates surpassing those of pristine noble metal-based catalysts. These promote future perspectives for the utilization of chemically synthesized MXenes as alternative photo-/electrocatalysts. Future research direction should focus on MXene synthesis and utilization for surface modification, composite formation, stabilization, and optimization in synthesis methods and post-synthesis treatments. This review highlights the progress in the understanding of fundamental mechanisms and issues associated with water splitting, influencing factors of MXenes, their value addition role, and application strategies for water splitting, including performance, challenges, and outlook of MXene-based photo-/electrocatalysts, in the last five years. [ABSTRACT FROM AUTHOR]

Platinum-based catalysts exhibit outstanding electrocatalytic performance in the hydrogen evolution reaction (HER). However, platinum-based catalysts face significant challenges due to their rarity and high cost. This paper endeavors to shed light on a promising alternative: polyoxometalate (POM)-based catalysts, which possess significant potential for the synthesis of non-noble metal-based catalysts for the HER. Utilizing POMs as raw materials to assemble POM-derived materials, including POM-derived crystalline materials, metal sulfides, phosphides, carbides, nitrides, and so on, has emerged as an effective approach for the synthesis of hydrogen evolution electrocatalysts. This approach offers advantages in both stability and electrocatalytic performance. This comprehensive review navigates through latest progress in the assembly strategy and HER performance of POM-based crystal materials, alongside discussion on transition metal compounds derived from POMs, such as carbides, phosphides, and sulfides. Besides, future developments in POM-derived electrocatalyst regulation of the electrochemical HER are prospected. [ABSTRACT FROM AUTHOR]

Development of the interfacial catalyst layer (IL) of a bipolar membrane (BPM) for its application in a water electrolyzer is carried out. Zirconium-oxide based three different metal-organic frameworks (MOFs: MOF-808, UIO-66, and Fe-MOF (dual metal)) were synthesized and separately incorporated as water-splitting IL to achieve three different BPMs. Catalytic activity of each BPM was separately evaluated and BPM with double metal clustered, Fe-based MOF (Fe-MOF) showed significantly higher water splitting performance compared to the other two containing single metal clustered (Zr) MOF. Subsequently, the catalyst loading at the interface layer was varied between 0.05, 0.2, 0.5, 1.0, and 2.0 mg∙cm−2, and BPMs with each composition were synthesized. The BPM with 1.0 mg∙cm−2 of Fe-MOF content showed the lowest (ever reported) water dissociation potential at 0.66 V, and this was ∼12% lower than the BPM without interface (synthesized inhouse). The water splitting performances along with electrochemical impedance spectroscopy (EIS) analysis were estimated and compared among three different electrode assemblies (MEAs) containing 0, 0.5, 1.0 mg∙cm−2 of Fe-MOF as interface catalyst of the single cell electrolyzer. Hydrogen production rates were separately monitored varying current density range: 0–500 mA∙cm−2, and 1.45 L∙h−1 (highest) was noted with 500 mA∙cm−2 for the MEA containing 1.0 mg∙cm−2 of Fe-MOF. This investigation is believed to be useful for designing different MOFs as IL of BPM and electrolyzers. [Display omitted] • Zirconium-oxide-based MOFs were synthesized for the interface catalyst layer in BPM. • Loading of Fe-MOF at BPM interface was optimized based on BPM I–V characteristics. • Double metal cluster Fe-MOF exhibited the lowest WD potential ever recorded, in reversed bias BPM. • Performances of single-cell BPM water electrolyzer for hydrogen production were investigated. [ABSTRACT FROM AUTHOR]

Solar photocatalytic hydrogen production shows promise in addressing global energy and environmental concerns. The limited efficiency of photocatalysts is mainly due to ineffective separation and transfer of photogenerated charges. To improve this, we enhance the TiO 2 –Ti 3 C 2 heterojunction by in-situ oxidation through interfacial engineering, resulting in a more compact composition. Subsequently, we anchor single-atom Pt at the TiO 2 –Ti 3 C 2 interface through photo-Ti 3 C 2 reduction. The in-situ growth of TiO 2 on Ti 3 C 2 introduces an interfacial driving force for carrier separation and provides a channel for electron transfer from TiO 2 to Ti 3 C 2. This further facilitates transfer onto Pt, shortening the migration distance and enhancing the photocatalytic efficiency. The best Pt/TiO 2 –Ti 3 C 2 composite demonstrates an impressive hydrogen precipitation efficiency of 767 μmol g−1 h−1, surpassing TiO 2 and Pt/TiO 2 by factors of 12 times and 1.46 times, respectively. Furthermore, we developed a higher efficiency photocatalyst using the molten salt method to avoid the risks associated with conventional hydrofluoric acid etching. This research opens up new possibilities for the preparation of MXenes interface-modified catalysts, offering a valuable avenue for future exploration in the field. • Ti 3 C 2 MXene was synthesized by F-free molten salt method. • TiO 2 –Ti 3 C 2 composites were successfully synthesized by in situ oxidation method. • Single-atom Pt interface engineered Pt–O electron transfer channel to shorten the charge migration distance. • TiO 2 –Ti 3 C 2 heterojunction interface Ti– O –Ti bridge promotes rapid electron transfer and separation. • Single-atom and heterojunction interface engineering synergistic effect to promote photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

Direct autothermal methane reforming is an energy-efficient way of hydrogen production. However, significant hot spot is always encountered near the reactor inlet, causing catalyst sinter and even reactor damage. Hence, bed temperature regulation by oxygen distributed feeding was numerically investigated using a one-dimensional heterogeneous model. Simulation results show oxygen feeding along full length of reactor leads to low methane and oxygen conversion despite avoiding hot spot. Elevating feeding temperature solves this problem, but requires extra heat. Shortening feeding length to 1/10 of reactor reduces maximum bed temperature by 100 K; Half oxygen fed into reactor inlet and the other along the length further reduces maximum bed temperature and avoids the transient runaway. Optimization results show that oxygen parabolically and totally fed along the front part of the reactor length shows better performance than that feeding half along reactor length and the other into reactor inlet. • Various O 2 feeding for autothermal methane steam reforming was studied in detail. • Maximal reactor temperature reduced avoiding runaway as 1/2 O 2 fed along 1/10 length. • O 2 parabolically fed along the front part of the reactor is the best to suppress hotspot. [ABSTRACT FROM AUTHOR]