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Green and sustainable power sources for next-generation electronics are being developed. A cellulose paper-based triboelectric nanogenerator (TENG) was fabricated to harness mechanical energy and convert it into electricity. This work proposes a novel approach to modify cellulose paper with natural dyes, including chlorophyll from spinach, anthocyanin from red cabbage, and curcumin from turmeric, to enhance the power output of a TENG. All the natural dyes are found to effectively improve the energy conversion performance of a cellulose paper-based TENG due to their photogenerated charges. The highest power density of 3.3 W/m2 is achieved from the cellulose paper-based TENG modified with chlorophyll, which is higher than those modified with anthocyanin and curcumin, respectively. The superior performance is attributed not only to the photosensitizer properties but also the molecular structure of the dye that promotes the electron-donating properties of cellulose. [ABSTRACT FROM AUTHOR]

Pulp and paper are gradually transforming from a traditional industry into a new green strategic industry. In parallel, cellulose-derived transparent paper is gaining ground for the development of advanced functional materials for light management with eco-friendly, high performance, and multifunctionality. This review focuses on methods and processes for the preparation of cellulose-derived transparent papers, highlighting the characterization of raw materials linked to responses to different properties, such as optical and mechanical properties. The applications in electronic devices, energy conversion and storage, and eco-friendly packaging are also highlighted with the objective to showcase the untapped potential of cellulose-derived transparent paper, challenging the prevailing notion that paper is merely a daily life product. Finally, the challenges and propose future directions for the development of cellulose-derived transparent paper are identified. [Display omitted] [ABSTRACT FROM AUTHOR]

Paper‐based microfluidics emerges as an innovative platform for constructing miniaturized electrochemical devices, which mainly benefit from the spontaneous capillary action of paper. Nevertheless, the capillary‐driven flow dynamics on paper are determined exclusively by the intrinsic properties of paper and fluidics, thus lacking the controllability that conventional pump‐based microfluidics can provide. Herein, an approach to regulating the capillary flow on paper is introduced by conjugating the outlets of microfluidic channels with a photothermal module for water evaporation. The capillary flow rate on paper can be handily regulated from 4 to 37 µL min−1 under controllable illumination conditions. As a proof‐of‐concept, prototypical paper‐based microfluidic fuel cells integrated with the photothermal module are constructed. Their peak power density can be boosted from 0.3 up to 2.1 mW cm−2 under the simulated sunlight irradiation. The influence of capillary flow rate on the fuel cell performance is further validated using multiphysics simulations. The present work not only provides a practically feasible method to boost the performance of paper‐based microfluidic fuel cells using solar energy, but also opens a new avenue for modulating the performance of paper‐based microfluidics, which has long been a challenge in this field. [ABSTRACT FROM AUTHOR]

Up-converting nanoparticles can be a demand for requirements in many areas, including bioimaging and conversion of energy, but also in the battle against counterfeiting. The properties of lanthanide ions make falsification difficult or even impossible using appropriately designed systems. The proposition of such an approach is the NaErF4:Tm3+@NaYF4 core@shell up-converting nanoparticles combined with transparent varnishes. Given the spectroscopic properties of Er3+ ions present in the fluoride matrix, the obtained up-converting nanoparticles absorb light by 808 and 975 nm wavelengths. The intentionally co-doped Tm3+ ions enable tuning characteristic green Er3+ emission to red luminescence, particularly desirable in anti-counterfeiting applications. The article includes a thorough analysis of structural and morphological properties. Moreover, this work shows that exclusive luminescent properties of NaErF4:Tm3+@NaYF4 NPs can be given to the transparent varnish, providing an excellent anti-counterfeiting system, revealing red emission under two different excitation wavelengths. [ABSTRACT FROM AUTHOR]

Up-converting nanoparticles can be a demand for requirements in many areas, including bioimaging and conversion of energy, but also in the battle against counterfeiting. The properties of lanthanide ions make falsification difficult or even impossible using appropriately designed systems. The proposition of such an approach is the NaErF4:Tm3+@NaYF4 core@shell up-converting nanoparticles combined with transparent varnishes. Given the spectroscopic properties of Er3+ ions present in the fluoride matrix, the obtained up-converting nanoparticles absorb light by 808 and 975 nm wavelengths. The intentionally co-doped Tm3+ ions enable tuning characteristic green Er3+ emission to red luminescence, particularly desirable in anti-counterfeiting applications. The article includes a thorough analysis of structural and morphological properties. Moreover, this work shows that exclusive luminescent properties of NaErF4:Tm3+@NaYF4 NPs can be given to the transparent varnish, providing an excellent anti-counterfeiting system, revealing red emission under two different excitation wavelengths. [ABSTRACT FROM AUTHOR]

In an era of modern smart technology, flexible electrodes are of great interest for different energy conversion as well as energy storage applications like solar cells, all solid-state batteries, and supercapacitors. Flexible metal oxide-based paper electrodes are advantageous in comparison to conventional electrodes due to their economical synthesis, biocompatibility, and environment-friendly characteristics. However, the electrical conductivity of paper electrodes is limited because of the insulating nature of natural fibers employed as a binder for the flexible matrix of metal oxides. The current study is an attempt to tune the electrical properties of lignocelluloses (natural fibers) and titanium dioxide (TiO 2) based paper electrodes by facile electrodeposition technique. The crystalline parts (e.g., TiO 2 , Ag, and Au) of the prepared composite sheets were characterized by XRD analysis while the surface morphology was studied by SEM. FTIR was used to characterize the organic matter in LC fibers by identifying various molecular stretching and vibrational modes of C, H, and O-containing molecules. Electric permittivity was measured as a function of electric field frequency at room temperature which revealed the value of 23. 5 (at 1 kHz) for the sample LC/TiO 2 /Ag 9000s indicating the best charge storing capability of the sample. Impedance analysis was employed to identify various charge carrier mechanisms active in the sheets. It was found through impedance analysis that there is an active diffusion-controlled impedance mechanism of Au-coated samples causing an increased conductivity via the ionic diffusion. This diffusion-controlled conduction was modeled by the Warburg element. The enhanced conductivity due to ionic diffusion makes these samples more useful as electrodes. Cyclic voltammetry (CV) measurements of the electrodeposited samples established the increase in conductive properties and efficient kinetics of LC/TiO 2 paper sheets. The current study suggests that Ag and Au-coated paper electrodes can be potential candidates for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

The heterocharge accumulated in the oil‐paper insulation system of the converter transformer will enhance the local electric field and cause insulation deterioration. Numerical simulation is an effective method to analyze heterocharge. Currently, the numerical simulation of heterocharge is mainly based on the bipolar charge transport (BCT) model and the impurity ion transport (IIT) model. However, the effects of temperature, conductivity, and thickness of oil‐impregnated paper on charge transport have not been considered in these models. In view of this, a modified charge transport (MCT) model by introducing the Maxwell–Wagner model and heat conduction equation is proposed in this paper based on the BCT model and IIT model. Then, the influence of multi‐factors (temperature gradient, moisture content, and oil‐impregnated paper thickness) on heterocharge accumulation is investigated by using the MCT model. The simulation results obtained by the MCT model are more consistent with the experimental results than the BCT model, which proves the accuracy and superiority of the MCT model. Moreover, the increase in temperature gradient, moisture content, and oil‐impregnated paper thickness will enlarge the ion dissociation rate, conductivity, and trap density, and thus promote the generation of heterocharge. In that respect, the MCT model is expected to optimize the insulation design and provide a reference for space charge dynamic simulation. [ABSTRACT FROM AUTHOR]

Sheet-like transition metal sulfides have promising applications in photocatalysis and energy conversion. This study provides a petal-like Cu 2 WS x nanosheet structure supported on carbon paper (CP) synthesized by a simple one-step solvothermal method. Cu 2 WS x microstructures with different morphologies were synthesized by solvothermal vulcanization of thioacetamide (TAA) at different concentrations. The Cu 2 WS x /CP was used as the counter electrode of DSSCs and compared with the Pt FTO electrode. It was proved that Cu 2 WS x -7 M/CP had the best electrocatalytic performance and obtained 9.01% photoelectric conversion efficiency. The different sulfide concentration changes the morphology of Cu 2 WS x and continuously affects the specific surface area and catalytic activity of the material. The better electrochemical performance shows that Cu 2 WS x /CP is expected to become a substitute for expensive Pt CE materials in dye-sensitized solar cells (DSSCs). [Display omitted] • One-step solvothermal method for the growth of petal-like Cu 2 WS x on carbon paper. • The effect of sulfide concentration on Cu2WSx was explored for the first time by TAA. • For the first time, Cu 2 WS x /CP was used as a counter electrode for DSSCs. • At a sulfide concentration of 7 M, Cu 2 WS x /CP exhibited a value of 9.01% PCE (Pt 7.67%). [ABSTRACT FROM AUTHOR]

Summary: Nonagonal Modular Multilevel Converter (MMC) is a new type of three‐port AC‐AC converter suited for applications in FFTS‐based offshore wind power. It can accommodate three AC ports with only nine branches, greatly reducing the cost and size of energy conversion. However, the multiplexing structure of nonagonal MMC inevitably increases the peak branch current resulting in high semiconductor ratings, which weakens its advantage in cost and size. Since the control degrees of freedom are reduced, traditional current attenuation methods are not applicable. To address this issue, in this paper, a parameter adjustment method is proposed for nonagonal MMC to reduce the current stress. By establishing the mathematical model of nonagonal MMC, phase angle difference between ports of nonagonal MMC is proved to be a key influencing factor of peak branch current. By adjusting phase angle difference, the average current stress of nonagonal MMC can be reduced by as great as 66.31%. Finally, the correctness of the conclusions of this paper is verified by RT‐LAB results. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have emerged as promising materials for ion conduction due to their highly tunable structures and excellent electrochemical stability. This review paper explores the mechanisms of ion conduction in COFs, focusing on how these materials facilitate ion transport across their ordered structures, which is crucial for applications such as solid electrolytes in batteries and fuel cells. We discuss the design strategies employed to enhance ion conductivity, including pore size optimization, functionalization with ionic groups, and the incorporation of solvent molecules and salts. Additionally, we examine the various applications of ion-conductive COFs, particularly in energy storage and conversion technologies, highlighting recent advancements and future directions in this field. This review paper aims to provide a comprehensive overview of the current state of research on ion-conductive COFs, offering insights into their potential to design highly ion-conductive COFs considering not only fundamental studies but also practical perspectives for advanced electrochemical devices. [ABSTRACT FROM AUTHOR]

In this paper, a proper noun "Region" is used for nm‐scale n‐type dopant‐rich region in p‐type Si crystal. Using this Region, certain solar cells have been assumed. By resonance absorption between photon energy and potential barrier of the Region, the cell can absorb most photons for visible light frequency without passing loss or thermal loss. This light absorption mechanism is different from conventional band gap absorption. Despite this benefit, output voltage is anticipated to decline according to the principle of detail balance. To control the decline, two methods are proposed in this paper. Theoretical energy conversion efficiencies for several cases are calculated with an ideal condition. The calculation result is over 70% as a theoretical value. [ABSTRACT FROM AUTHOR]

With the development of science and technology, the energy issue has gradually become a topic of global common exploration. According to the relevant information, this paper designed a distributed new energy system based on the blockchain consensus algorithm. The system took the distributed new energy system as the main body, integrated it with blockchain technology, and finally formed a distributed new energy system based on blockchain consensus algorithm. The feasibility of the system was finally determined after the technical tests of voltage detection, power allocation, information collection, and algorithm security. In order to understand the differences between the performance of this system and the traditional system, this paper has made several performance data comparative analysis tests for this system and the traditional system. The test items included energy conversion utilization rate, energy storage, energy use price, energy cleanliness, energy access rate, energy use, etc. Finally, the relevant data of commercial power consumption and residential power consumption accounting for 30 % and 47 % of the total power consumption were obtained, and the data was used to analyze the source of power access. The proportion of green energy is 10 % and 17 %, respectively. According to a series of operation processes such as design, experiment, and analysis, it was finally determined that the system was feasible and effective. [ABSTRACT FROM AUTHOR]

This paper is a fundamental exploration of the dynamic area of nanocatalysis, offering a detailed analysis of recent advancements and practical applications. Tailored for researchers and professionals, this article begins with a historical overview, emphasizing nanocatalysis' pivotal role in contemporary science and industry. It delves into foundational principles, covering nanoparticle synthesis, characterization, surface chemistry, and reactivity mechanisms at the nanoscale. Advanced sections explore the design of nanomaterials for catalysis, hybrid catalyst synthesis, and the integration of computational approaches. Mechanistic insights are presented through a detailed examination of reaction pathways and cutting-edge spectroscopic techniques. Practical applications span energy conversion, sustainable synthesis, and environmental remediation, with illustrative case studies. The article concludes by addressing current challenges, outlining future perspectives, and highlighting emerging trends, making it an essential guide for those navigating the multifaceted landscape of nanocatalysis. [ABSTRACT FROM AUTHOR]

Microfluidic fuel cells (μFCs) offer a promising avenue for generating energy from glycerol, utilizing flow‐through electrodes to enhance reactant utilization. However, the cathodic reaction must efficiently consume the electrons harvested at the anode side to unlock its full potential. Here, we explore the feasibility of employing liquid oxidants as an alternative to O2 reduction on metal‐free carbon paper (CP) cathodes. We investigated the half‐cell reactions and the energy conversion in a new reusable 3D‐printed μFC. Half‐cell reactions predict spontaneous reactions by coupling glycerol electrooxidation in an alkaline medium with O2, Na2S2O8, and HClO from commercial bleach in an acidic medium. The μFC printed using the stereolithography apparatus technique build microchannels to place the Pt/C/CP anode and CP cathodes. The glycerol/Na2S2O8 μFC delivered a maximum of 32.4 mW cm−2, while glycerol/HClO μFC displayed 55.9 mW cm−2. This research sheds light on the potential of liquid oxidants as effective alternatives to O2 reduction, presenting a pathway toward optimizing μFCs and their practical applications in energy conversion from glycerol. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have gained much attention in recent years because of their improved energy conversion efficiency, simple fabrication process, low processing temperature, flexibility, light weight, and low cost of constituent materials when compared with their counterpart silicon based solar cells. Besides, stability and toxicity of PSCs and low power conversion efficiency have been an obstacle towards commercialization of PSCs which has attracted intense research attention. In this research paper, a Glass/Cu2O/CH3NH3SnI3/ZnO/Al inverted device structure which is made of cheap inorganic materials, n-type transparent conducting oxide (TCO)-free, stable, photoexcited toxic-free perovskite have been carefully designed, simulated and optimized using a one-dimensional solar cell capacitance simulator (SCAPS-1D) software. The effects of layers' thickness, perovskite's doping concentration and back contact electrodes have been investigated, and the optimized structure produced an open circuit voltage (Voc) of 1.0867 V, short circuit current density (JSC) of 33.4942 mA/cm2, fill factor (FF) of 82.88% and power conversion efficiency (PCE) of 30.17%. This paper presents a model that is first of its kind where the highest PCE performance and eco-friendly n-type TCO-free inverted CH3NH3SnI3 based perovskite solar cell is achieved using all-inorganic transport materials. [ABSTRACT FROM AUTHOR]

The energy conversion performance of commercial photovoltaic (PV) systems is only 15–20 percent; moreover, a rise in working temperature mitigates this low efficiency. To enhance their performance and prevent damage, researchers test new technologies and integrate heat recovery devices with PV systems. Concentrated photovoltaic systems (CPVs) are especially vulnerable to high radiation levels. This paper explores novel cooling techniques for PV systems, an area that has not been extensively investigated before. The cooling methods are categorized into front-surface and back-surface cooling methods, offering a unique perspective on how to keep PV systems cool. Moreover, the paper delves into the advancements made in PV cooling systems and CPVs, shedding light on the cutting-edge developments in this field. The results demonstrate the profound impact of various operational factors, such as radiation and wind speed, on the selection of suitable cooling systems or heat recovery methods. These findings unveil the crucial importance of considering these factors when choosing cooling techniques, adding a compelling dimension to the research. For example, it was depicted that optical cooling techniques can enhance the performance of PV systems by up to 4.2% and the solar-to-heat conversion efficiency by up to 47%. Furthermore, this research ventures into uncharted territory by subjecting both the front and back sides of the PV module to active and passive cooling techniques under differing work conditions. The comprehensive list provided here exhaustively describes the advantages, disadvantages, and developments of each technique, revealing the novelty of the approaches explored in this paper. It was reported that back cooling techniques can decline the cell temperature of PV systems by up to 57.8% and grow the electrical and thermal efficiencies by up to 82.6% and 97.75%, respectively. The groundbreaking nature of this research lies in its ability to empower decision-makers to select the optimal cooling system based on specific requirements and environmental factors, thereby bridging the gap between theory and practical application. The paper also introduces a new concept of cooling using hydrogel, a 3D porous network structure that can enhance photovoltaic energy conversion and storage, and reviews two recent studies that demonstrated the effectiveness of hydrogel cooling methods for PV panels. Moreover, the paper discusses the issue of dust deposition and mitigation, which affects the performance and lifetime of PV modules, and evaluates various methods for cleaning or reducing dust on PV panels, such as manual, passive, self-cleaning, and mechanical. [ABSTRACT FROM AUTHOR]

This paper delves into the synthesis strategies of molybdenum disulfide (MoS2) nanomaterials and their prospective applications in the fields of energy conversion and storage. Through a comprehensive analysis of various synthesis methods, including solvothermal and sol-gel processes, the specific impacts of these methods on the morphology and properties of MoS2 nanostructures are revealed. The study indicates that MoS2 nanomaterials with optimized electronic properties and surface activity can be fabricated by precisely controlling the synthesis conditions. These materials demonstrate exceptional performance in applications such as lithium-ion batteries and photodetectors, especially in enhancing battery charge-discharge cycle stability and improving photoelectric conversion efficiency. The paper further discusses the challenges faced in the development of MoS2 applications, particularly in terms of the scalability of material synthesis and consistency of performance. Lastly, the article presents a vision for future research directions, emphasizing the potential to broaden the application of MoS2 in high-performance energy devices through innovative synthesis strategies and material structure optimization. [ABSTRACT FROM AUTHOR]

A general mathematical model is developed for electrochemical energy conversion in paper-based, capillary-driven, microfluidic flow cells. A two-dimensional version of the model is implemented to simulate a novel flow cell of this kind called PowerPAD. The methodology developed is validated against experimental data for this particular cell under both steady and unsteady modes of operation. It is shown that a 2D model can represent a 3D cell in unsteady flows provided that the Nernst-Planck equation is properly refined. The results are interpreted in terms of transient back-diffusion and crossover of the reactant species which are found to be the key factors controlling the electrochemical performance of this cell. The validated model is used to enhance the power output, runtime, and energy efficiency of this particular cell through altering its flow architecture and microstructure of electrodes and absorbent pad. The refined cell design is shown to roughly triple the power output and runtime of the device. The optimized design also outperforms the original design in terms of energy efficiency. The developed mathematical model, the fundamental understanding, and the proposed cell design may be utilized to develop new devices and concepts for capillary-based electrochemical systems, including biodegradable batteries, fuel cells, and electrolyzers. [Display omitted] • A dynamic mathematical model is developed for paper-based microfluidic flow cells. • A 2D model can represent a 3D cell subject to Nernst-Planck equation refinement. • The model reveals the unique working mechanism of imbibition and back-diffusion. • Crossover is identified as the key limiting factor for cell performance and runtime. • An optimized cell design is proposed with 3x performance improvement. [ABSTRACT FROM AUTHOR]

Because of the ever-growing world population and the burgeoning of economic advancements, solving both environmental and energy-driven challenges are of prime concern. In the view of the current scenario, photocatalyst as an environmentally friendly method has rapidly emerged due to its prominent function in the conversion of solar energy for overcoming two aforementioned serious challenges. Recently, numerous attempts have been carried out for enhancing the visible-light photoactivity by application of TiO2 as photocatalyst because of its extensive scope of employment in both environmental-related and energy regions. Nevertheless, the photocatalytic performance of TiO2 under visible-light illumination is seriously restricted by the absorption edge in the ultra-violet range and the rapid electron–hole recombination. Extensive research has been dedicated to bypassing the shortcomings of titanium dioxide and hence improving its photoactivity under visible light. To be more specific, some approaches for modification of TiO2 properties include tetragonal BaTiO3 nanoparticles, ultrasound-assisted preparation of rGO/TiO2 nanocomposite, BaTiO3/ZnO heterostructured photocatalyst, Sol pH-induced ZnO-TiO2 multi-phase composite, BaTiO3/g-C3N4 heterojunction, TiO2-zeolite nanocomposite, etc., were explored and developed. Moreover, in this review paper, the authors briefly evaluated various nano-TiO2 synthesis methods, such as sol-gel, hydrothermal, solvothermal, and mixed ones. Despite the excellent achievements and the improvements in this area, the probability of nano-TiO2 modification for highly efficacious photocatalyst systems has not been completely explored and its commercialisation still is problematic. As a result, still, intensive research efforts require to effectively overcome those challenges for reaching a bright future in the wastewater treatment process with minimum environmental adverse effects. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a novel three‐phase hybrid multilevel inverter (TPHMLI) designed for grid‐connected solar photovoltaic (SPV) systems. The TPHMLI combines series‐connected bridge topologies of half and full circuits to generate 11 stages of line load voltages, reducing the need for DC sources. It also introduces an improved pulse width modulation (PWM) approach, addressing computational challenges and high‐frequency triggering issues. Practical validation in a laboratory setting demonstrates the MLI's functionality and effectiveness. Furthermore, the advanced MLI topology successfully addresses design issues in grid‐integrated SPV structures, including power quality, efficiency, and reliability. It excels in managing reactive power and fault obstructive capabilities. Extensive simulations using MATLAB/Simulink confirm its superior performance, making it a promising solution for power conditioning units in grid‐connected solar PV systems. This research contributes to clean and sustainable energy conversion technologies, enhancing power quality and cost‐effectiveness, with significant potential for practical applications in the renewable energy sector. [ABSTRACT FROM AUTHOR]

This paper presents a Hybrid Renewable Energy system combining multiple sources of renewable energy, such as PV, Wind, and energy storage devices, to provide a reliable and sustainable power supply. Cascaded converters are used to efficiently transform and manage the energy from these sources. To achieve optimal performance and reliable operation, a real-time closed-loop control algorithm is designed and implemented for the cascaded converter. The control algorithm facilitates the smooth integration of energy from various renewable sources, optimizing the utilization of available resources and ensuring a consistent power supply. The algorithm maximizes the energy conversion efficiency of the cascaded converter, reducing energy losses and minimizing waste. It also optimizes the integration of renewable sources, regulates output parameters, and ensures efficient energy conversion. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) are widely regarded as one of the most promising thermal energy storage technologies, owing to their outstanding latent heat storage density and controllable thermal storage/release characteristics. However, pure PCM usually has certain limitations in terms of electric‐, photo‐, and magnetic‐thermal conversion. In recent years, research on enhancing these properties through the addition of various fillers has garnered widespread attention. Herein, this paper elaborates on the modification of PCM for electric‐thermal, photo‐thermal, and magnetic‐thermal conversion, including their respective modification strategies, properties, and applications. Therein, a comparative analysis is conducted on the electric‐, photo‐, and magnetic‐thermal conversion efficiency of PCM with different fillers. Further, a summary and analysis are conducted on the addition of some fillers to PCM, which simultaneously improves the conversion performance of the two or three mentioned above, enabling multiple energy conversion. Finally, existing problems, solutions, and future development directions are put forward. [ABSTRACT FROM AUTHOR]

A liquid piston Stirling engine is an external combustion engine that uses air and water under atmospheric pressure as its working fluids. Resulting from its uncomplicated design and the capacity to operate under relatively low temperature differentials of less than 100 °C, it has attracted considerable attention in recent years. This paper presents the fundamental characteristics of the liquid piston engine combined with a self-rectifying turbine for the advancement of thermal generators. When the turbine is installed in the water region rather than in the air region, it exhibits unidirectional rotation with a rotational speed directly proportional to the velocity amplitude of the reciprocating axial flow. Additionally, the acoustic impedance within the duct section containing the turbine is determined, demonstrating that the real part of impedance rises with increasing axial velocity, indicating a loss mechanism similar to the minor loss. Furthermore, the installation of the turbine results in a breakdown of symmetry in the engine oscillation mode. To maintain symmetry and improve system design, future developments must consider the installation of a turbine in each unit. These findings can pave the way to the design of liquid piston Stirling engines and their applications in thermal energy conversion. [ABSTRACT FROM AUTHOR]

Energy conversion from heat to acoustics remains one of the major challenges in high-performance propulsion systems. It has been found that structure vibration may lead to combustion instability, though the mechanism behind this is still unknown. In this paper, the impact of axial mechanical vibration on a premixed methane flame is studied experimentally, using an electromagnetic vibration exciter to drive the flame burner. The burner's movement is measured by the accelerometers. The flame morphology is captured by a high-speed camera with an image intensifier via long exposure times, and the local unsteady heat release rate is measured by a photomultiplier tube. The flame transfer functions are analyzed at various equivalence ratios and mean flow velocities. The results indicate that the mechanically induced vibration leads to a clear bandpass filtering effect on the premixed flame across different equivalence ratios and flow velocities without altering the peak frequency. In addition, as the vibration amplitude increases, the flame response saturates and the flame tips become wrinkled, especially when the driving frequency aligns with the response peak. [ABSTRACT FROM AUTHOR]

Summary This paper describes a novel seven‐level (7L) inverter. The suggested topology offers a 7L output voltage and a threefold gain by using proper capacitor values. The suggested topology reduces the spike current induced by the capacitor by the use of a resonant inductor. The suggested inverter's performance under various loads and situations is compared with those found in existing literature. The simulation findings confirm the system's strong performance in terms of component count, control circuit simplicity, and possible cost reductions, while retaining similar or enhanced performance metrics as compared with the aforementioned topologies. A laboratory setup is used to validate the feasibility of the suggested topology and provide solid evidence of its effectiveness. Furthermore, discussions about the possible uses of this structure in energy conversion are conducted. [ABSTRACT FROM AUTHOR]

Wave energy has a high energy density and strong predictability, presenting encouraging prospects for development. So far, there are dozens of different wave energy devices (WECs), but the mechanism that ultimately converts wave energy into electrical energy in these devices has always been the focus of research by scholars from various countries. The energy conversion mechanism in wave energy devices is called PTO (power take-off). According to different working principles, PTOs can be classified into the linear motor type, hydraulic type, and mechanical type. Hydraulic PTOs are characterized by their high efficiency, low cost, and simple installation. They are widely used in the energy conversion links of various wave energy devices. However, apart from experimental methods, there is currently almost no concise numerical method to predict and evaluate the power generation performance of hydraulic PTO. Therefore, based on the working principle of hydraulic PTO, this paper proposes a numerical method to simulate the performance of a hydraulic PTO using MATLAB(2018b) Simulink®. Using a point-absorption wave energy device as a carrier, a float hydraulic system power-generation numerical model is built. The method is validated by comparison with previous experimental results. The predicted power generation and conversion efficiency of the point-absorption wave energy device under different regular and irregular wave conditions are compared. Key factors affecting the power generation performance of the device were investigated, providing insight for the subsequent optimal design of the device, which is of great significance to the development and utilization of wave energy resources. [ABSTRACT FROM AUTHOR]

In this paper, the effect of doping and nanostructuring on the electrostatic potential across the electrochemical interface between a transition metal oxide and a water electrolyte is investigated by means of the Poisson–Boltzmann model. For spherical nanoparticles and nanorods, compact expressions for the limiting potentials at which the space charge layer includes the whole semiconductor are reported. We provide a quantitative analysis of the distribution of the potential drop between the solid and the liquid and show that the relative importance changes with doping. It is usually assumed that high doping improves charge dynamics in the semiconductor but reduces the width of the space charge layer. However, nanostructuring counterbalances the latter negative effect; we show quantitatively that in highly doped nanoparticles the space charge layer can occupy a similar volume fraction as in low-doped microparticles. Moreover, as shown by some recent experiments, under conditions of high doping the electric fields in the Helmholtz layer can be as high as 100 mV/Å, comparable to electric fields inducing freezing in water. This work provides a systematic quantitative framework for understanding the effects of doping and nanostructuring on electrochemical interfaces, and suggests that it is necessary to better characterize the interface at the atomistic level. [ABSTRACT FROM AUTHOR]

With the integration and miniaturization of modern equipment and devices, porous polymers, containing graphene and its derivatives, with flame-retardancy have become a research hotspot. In this paper, the expanded properties and high-end applications of flame-retardant porous materials containing graphene and its derivatives were discussed. The research progress regarding graphene-based porous materials with multiple energy conversion, thermal insulation, an electromagnetic shielding property, and a high adsorption capacity were elucidated in detail. The potential applications of materials with the above-mentioned properties in firefighter clothing, fire alarm sensors, flexible electronic skin, solar energy storage, energy-saving buildings, stealth materials, and separation were summarized. The construction strategies, preparation methods, comprehensive properties, and functionalization mechanisms of these materials were analyzed. The main challenges and prospects of flame-retardant porous materials containing graphene and its derivatives with expanded properties were also proposed. [ABSTRACT FROM AUTHOR]

Developing advanced anode materials for sodium‐ion batteries (SIBs) is a frontier and hotspot research for clean and sustainable electricity energy storage and conversion. However, it is still challenging to obtain anode materials with high stability, multiple active sites, and high conductivity. In this paper, an advanced metal–organic framework (MOF)‐based anode material (Co‐HITP), which integrates multiple advantages into one, is successfully synthesized through a sodiation‐stimulated in situ reconstruction. The Co‐HITP possesses a stable single‐crystal structure, expanded spacing layers, abundant sites, and good conductivity, and exhibits superior properties with ultra‐long cycling stability (ultralow decay rate ≈0.001% per cycle after 15 000 cycles at 8 A g−1), high reversible capacity (450.1 mA h g−1 at 0.2 A g−1), and excellent rate performance. Both experimental results and theoretical calculation reveal that the anode remains a stable structure after long cycling, attributed to the single‐crystal structure with d‐π hybridization and π–π interaction, and the minimum structural unit stores 6Na+ ions of C═N sites and 8Na+ ions of aromatic rings. This discovery is significant for developing advanced anode materials with integrated advantages for SIBs. [ABSTRACT FROM AUTHOR]

In the field of research on renewable energy conversion and storage methods, the development of catalysts with excellent properties and outstanding stability for oxygen evolution reaction (OER) acting at various pH values has become a much-anticipated research focus. RuO 2 as a benchmark OER catalyst, its wide application has always been limited by slow reaction kinetics and limited persistence. In this paper, Mn-doped RuO 2 material was developed and the optimum doping ratio was identified for using as an OER electrocatalyst under general purpose pH media. Mn 0.1 Ru 0.9 O 2 exhibited a lower overpotential value of 224 mV in acidic environment with a Tafel slope value of 51.62 mV dec−1. Moreover, in alkaline and neutral environments, overpotentials of 231 mV and 376 mV were required to obtain a current density of 10 mA cm−2, respectively. In addition, through continuous stability testing over 24 h in alkaline, acidic and neutral solutions, it has been further demonstrated that the Mn-doped RuO 2 material exhibits extremely high stability. The advancements in this research offer crucial insight into the rational development of efficient and durable RuO 2 -based catalysts. [Display omitted] • Mn 0.1 Ru 0.9 O 2 is successfully synthesized by a facile sol-gel method. • Mn doping modulates the electronic structure of RuO 2. • The catalyst exhibits enhanced OER activity and stability in pH-Universal media. [ABSTRACT FROM AUTHOR]

With the energy revolution and the proposal of "double carbon" background, hydrogen energy with rich reserves, clean and low carbon and broad application prospects has gradually become a global hot spot. The combination of seawater hydrogen production and offshore wind power is undoubtedly the focus of research in this field. However, this new research field is not yet mature and is still in its infancy, so in order to reduce unnecessary losses, it is crucial to identify the key risks and prevent them. Secondly, the adaptability of a single model is no longer reliable for the risk assessment of this emerging field, especially the conversion from offshore wind to electric energy to hydrogen energy. Based on the above, this paper first considers the ambiguity and uncertainty of information, as well as the risk attitude of decision makers in the evaluation process, and develops a novel evaluation model. The reliability and optimization of the model are verified by sensitivity analysis and comparative analysis, and a case is introduced for practical analysis. The final results show that the key risks of hydrogen production from offshore wind power are seawater electrolysis technology, hydrogen energy storage technology and high-quality wind energy resources. The overall risk is 0.4198, which is medium risk. Decision-making managers can make targeted risk prevention to reduce losses and promote the stable operation of offshore wind power hydrogen production. [Display omitted] • Offshore wind power combined with seawater hydrogen production. • An improved model based on spherical fuzzy theory and cumulative prospect theory. • Taking China 's first large-scale offshore wind power hydrogen production project as a case study. • Key risks: seawater electrolysis technology, hydrogen storage technology and wind energy resources. • The quantitative result of the overall risk assessment was 0.4198. [ABSTRACT FROM AUTHOR]

This paper proposes a new type of cogeneration system coupled by Organic Rankine Cycle (ORC), Absorption Heat Pump (AHP), and Compression Heat Pump (CHP). The new system can meet the needs of different scenarios. Simulations were conducted to analyze the effect of different factors on the parameters and performance indexes of the new system and compared with the system of ORC, AHP, CHP. The results showed that the factors of flue gas temperature at evaporator1 outlet and CHP have the greatest effect on the parameters and performance indexes of the Organic Absorption-Compression Coupling Heat Power (OACCHP) system, and the effect of AHP on the parameters and performance indexes of the OACCHP system can be ignored. In the given range of flue gas temperature at evaporator1 outlet, the heat production of total and net work is reduced by 1.17% and 33.33%, respectively. In a given range of CHP evaporation temperature, the heat production of the total is reduced by 5.74%. In the given range of the outlet temperature of the gas cooler, the heat production of the total is increased by 10.58%. In a given working condition, compared with the single ORC system, the single CHP system, and the single AHP system, the thermal efficiency, COP, and energy earning rate of the OACCHP system are increased by up to 755.49%, 59.8%, 5.8%, respectively. Finally, the optimal operating conditions for different scenarios were determined. [ABSTRACT FROM AUTHOR]

This paper presents a complete electromechanical (EM) model of piezoelectric transducers (PTs) independent of high or low coupling assumptions, vibration conditions, and geometry. The PT's spring stiffness is modeled as part of the domain coupling transformer, and the piezoelectric EM coupling coefficient is modeled explicitly as a split inductor transformer. This separates the coupling coefficient from the coefficient used for conversion between mechanical and electrical domains, providing a more insightful understanding of the energy transfers occurring within a PT and allowing for analysis not previously possible. This also illustrates the role the PT's spring plays in EM energy conversion. The model is analyzed and discussed from a circuits and energy harvesting perspective. Coupling between domains and how loading affects coupled energy are examined. Moreover, simple methods for experimentally extracting model parameters, including the coupling coefficient, are provided to empower engineers to quickly and easily integrate PTs in SPICE simulations for the rapid and improved development of PT interface circuits. The model and parameter extractions are validated by comparing them to the measured response of a physical cantilever-style PT excited by regular and irregular vibrations. In most cases, less than a 5–10% error between measured and simulated responses is observed. [ABSTRACT FROM AUTHOR]

The power sector confronts a crucial challenge in identifying sustainable and environmentally friendly energy carriers, with hydrogen emerging as a promising solution. This paper focuses on the modeling, analysis, and techno-economic evaluation of an independent photovoltaic (PV) system. The system is specifically designed to power industrial loads while simultaneously producing green hydrogen through water electrolysis. The emphasis is on utilizing renewable sources to generate hydrogen, particularly for fueling hydrogen-based cars. The study, conducted in Skikda, Algeria, involves a case study with thirty-two cars, each equipped with a 5 kg hydrogen storage tank. Employing an integrated approach that incorporates modeling, simulation, and optimization, the techno-economic analysis indicates that the proposed system provides a competitive, cost-effective, and environmentally friendly solution, with a rate of 0.239 $/kWh. The examined standalone PV system yields 24.5 GWh/year of electrical energy and produces 7584 kg/year of hydrogen. The findings highlight the potential of the proposed system to address the challenges in the power sector, offering a sustainable and efficient solution for both electricity generation and hydrogen production. [ABSTRACT FROM AUTHOR]

Rock brittleness and brittle failure play significant roles in deep underground space stability, unconventional gas extraction drilling, hydraulic fracturing efficiency, and coal mining disaster prevention, and these rock engineering processes involve cyclic loading conditions. However, nearly all the existing rock brittleness indices (BIs) are conducted with monotonic loading, and the variation in brittleness with cyclic loading has not been comprehensively studied. This study rearranged energy evolution and conversion based on stress–strain curves to investigate the existing energy-based rock BIs. Monotonic and cyclic triaxial compression experiments were conducted on red sandstone specimens to investigate the differences in the mechanical properties. This paper proposes a BI based on post-peak energy conversion to evaluate rock brittleness under monotonic and cyclic loadings. This index is defined as the ratio of the extra inputted/released energy to the fracture energy. The results showed that the variations in mechanical parameters in the two types of experiments were consistent at the pre-peak stage and different at the post-peak stage. The value of the proposed BI revealed that rock brittleness under cyclic loading was lower, which conformed with the qualitative analysis of stress–strain curves and macroscopic failure plane. The proposed BI strongly correlated with the mechanical parameters under monotonic and cyclic loading. The applicability verification, compared with the existing energy-based BIs for different rock types, confining pressures, and inclination angles of bedding planes, showed that the novel BI exhibited an excellent linear correlation with the strength parameters and had broad applicability. [ABSTRACT FROM AUTHOR]

Clean energy devices have a great ability to change the world because they strengthen the economy and preserve society. The continuous improvement and progress in nanomaterials and nanotechnology have a great role in human life. The increasing prevalence of PEM fuel cells makes them one of the most viable sustainable energy sources. Nanostructured materials synthesis methodologies have introduced a breakthrough and found to overcome the obstacles for PEMFC commercialization. Amongst them, wet chemical approaches are rapidly expanding and beneficial for the fabrication of nanoparticles since they contribute toward the attainment of a range of essential nanoparticle characteristics like sizes, morphologies, structures, and phases. Wet chemical manufacturing enables fine-tuning of reaction parameters to generate the desired nanomaterials. This review article focuses on the latest improvements in wet chemical methods to better regulate the quality of nanomaterials. This paper examines how wet chemical approaches (hydrothermal synthesis, spray pyrolysis, sol-gel processing, and co-precipitate synthesis, among others) can contribute to the scalable manufacturing of nanoparticles to uphold rising industrial requirements. And how wet chemical methods have a significant influence on power generation systems (Fuel cells) along with their pros and cons. This review carefully analyzes and summarizes synthetic methods and optimized factors in order to prepare nanoparticles and carefully analyzes the reported data. In this paper, the electrochemical analysis, morphological evaluation, compositional analysis, and performance testing of materials produced using wet chemical techniques have been investigated. Recent signs of progress and innovative techniques used to overcome the complexities of synthetic nanoparticle processing. This article is a holistic approach including social, economic, and ecological aspects in the wet chemical process and will certainly help in the fabrication, and application of nanoparticles for PEM Fuel cells. [Display omitted] • Introduction to the status of materials synthesis in energy generating devices. • Overview of wet chemistry Approaches for PEMFC. • Impact of synthesis parameters on properties of materials. • Pros and Cons of wet chemistry techniques for material synthesis. [ABSTRACT FROM AUTHOR]

A cascaded H-bridge multilevel converter topology is the ultimate solution for energy conversion in various industrial applications due to its exceptional features, such as high modularity and fault-tolerant capability. However, two circumstances can lead to unbalanced operation of the inverter, potentially causing a decrease in its reliability and survivability: unequal DC voltage sources and faulty cells. In recent decades, scientists and engineers have conducted intensive research and meaningful studies to propose control solutions capable of maintaining the stable and continuous operation of the inverter under these operational concerns. Typically, each challenge is addressed separately using a distinct compensation control scheme in the existing literature. The paper aims to offer a comprehensive review of the existing compensation control schemes appropriate for CHBMIs operating under unbalanced conditions. It overviews the most popular control schemes and summarizes their usefulness in such scenarios. The theoretical foundations of each control scheme are presented and discussed, including their operating principles, implementation schemes, advantages, and disadvantages. The paper concludes with suggested future trends that require further research for CHBMIs' continued growth and adoption in various industrial applications. [ABSTRACT FROM AUTHOR]

This paper presents a three-port isolated hybrid converter (3PIHC) with extended phase-shift modulation (EPM) to reduce voltage and current stress in the converter for DC microgrid applications. A high-frequency transformer with three independent windings is employed for isolating three ports in the converter. A wide variation in voltage transformation ratio is one of the main concern in DC microgrid, which need to be addressed for effective power conversion and utilization of the energy generation systems. Traditional phase-shift modulation (TPM) in 3PIHC leads to high conduction and core losses in the converter under wide variation in voltage transformation ratio. This paper proposes an extended phase-shift modulation in 3PIHC for different sequence of voltage transformation ratios between port 1 and port 2 (m 12) and between port 1 and port 3 (m 13) , which is a cost-effective solution for reducing losses in the converter. The peak current at all ports and power equations in 3PIHC are deduced, and the computational method for obtaining the phase-shift values with minimum current stress is explained in detail. A comparative evaluation study proves that the proposed three-port converter with EPM outperforms to TPM in the aspects like low current stress, reduced semiconductor switching losses and transformer losses for wide variation in voltage transformation ratios. A hardware prototype of the proposed converter is built, and the results are evaluated and presented. [ABSTRACT FROM AUTHOR]

As the goal of "double carbon", integrated energy systems aiming at the development of low-carbon economy are developing rapidly, and carbon capture and other emission reduction technologies are gradually gaining more extensive development space. For controlling carbon emissions and enhance the consumption of renewable energy. This work proposes to introduce carbon capture technology in the framework of integrated energy system and optimize the energy dispatching of integrated energy system in multiple time scales, and design a multi-time scale optimization model of integrated energy system with carbon capture. Based on the basic architecture of a low-carbon integrated energy system, this study analyzes the power characteristics of each unit of the integrated energy system, which consists of thermal power units, gas turbines, electric boilers, batteries, gas storage, heat storage, etc. By studying the energy conversion and storage processes of each unit, a power model of each unit of the integrated energy system is established. On this basis, the relationship between carbon emissions and unit output of thermal power units and gas turbines was studied, and a carbon emission model for the energy supply unit in the comprehensive energy system was established. At the same time, in order to solve the problem of carbon emission reduction under the day ahead scheduling plan of the integrated energy system, considering the emission reduction goals and system operation security factors, the study analyzed the economic model and carbon emission model of the integrated energy system, established the day ahead low-carbon scheduling model of the integrated energy system, and reasonably planned the output of each unit that can achieve the carbon emission reduction goals on the premise of meeting the balance of supply and demand. The innovation of the research method of this paper is that this paper establishes a multi time scale rolling optimization model under the emission reduction goal of the integrated energy system. Based on the day ahead scheduling scheme obtained in the day ahead low-carbon scheduling phase, the day ahead plan is first revised through 4 h rolling scheduling in the day; Then, with the goal of minimizing the adjustment amount, fine tune the unit output within 15 minutes to provide a daily output plan for subsequent low-carbon emission reduction targets. The outcomes indicate that in the practical application, the carbon emission of the optimized model in the peak hour 11:00 to 12:00 phase is 118 tons, which is 7 tons less than the 125 tons of the traditional model. In summary, it demonstrates that the studied multi-timescale optimization model of integrated energy system with carbon capture has good application. We have studied and analyzed the low-carbon implementation mechanism of coordinated cooperation in multiple time scales, and constructed a multi time scale rolling optimization model, laying a theoretical foundation for subsequent low-carbon scheduling research. This enables the system to formulate more accurate and reasonable scheduling plans, while improving the low-carbon performance and economic benefits of the system, providing reference for the low-carbon development of the power system. [ABSTRACT FROM AUTHOR]

In this paper, robust predictive control (RPC) based on direct torque control space vector modulation (DTC-SVM) of the doubly fed induction generator wind turbine system (DFIG-WTS) is investigated to improve energy capture effectiveness. A novel cost function is introduced for the predictive speed regulator where the aerodynamic torque is considered as an unknown perturbation. This technique is designed to improve dynamic performance such as reference tracking, disturbance rejection, and robustness to parameter variations. The use of the DTC-SVM technique enhances performance in terms of constant switching frequency and reduced torque-flux ripples. The simulation results using real-time MATLAB/Simulink demonstrate the feasibility and validity of the proposed strategy, where very satisfactory performance has been achieved. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction reaction (NO 3 RR) provides a promising method for ammonia (NH 3) producing. It is urgent to develop efficient catalysts with improved NO 3 RR performance. In this paper, Cu 3 P@Co(OH) 2 /CF heterostructure catalyst is constructed by electrodeposition of cobalt hydroxide (Co(OH) 2) nanosheet on the surface of copper phosphide (Cu 3 P) nanorod, and used as a self-supporting cathode for electrocatalytic reduction of nitrate to ammonia. The NH 3 yield reaches 0.19 mmol h−1 cm−2 at a potential of −0.17 V vs. RHE, and the faraday efficiency (FE) is 86.7 %. The study manifests that the built-in electric field generated at the p-n heterojunction interface optimizes the electron migration kinetics, and promotes the adsorption of nitrate and the convention of intermediate product NO 2 − into ammonia. As a consequence, the selectivity of NH3 is improved. The Zn-nitrate battery is assembled with the designed catalyst as the cathode, to reach a peak power density of 5.16 mW cm−2. The prepared catalyst realizes three effective functions: power output, ammonia synthesis, and nitrate pollutants treatment. [Display omitted] • Cu 3 P@Co(OH) 2 /CF heterostructure material was synthesized by low temperature phosphating and electrodeposition methods. • The built-in electric field at the p-n heterojunction promotes the convention of intermediate NO 2 − into ammonia. • Cu 3 P@Co(OH) 2 /CF effectively promotes the *H pathway for NO 3 − reduction to NH 3. • Zn-nitrate battery was built with Cu 3 P@Co(OH) 2 /CF cathode to realize multi-functional applications. [ABSTRACT FROM AUTHOR]

The ocean energy resources hold the promise of a sustainable solution within global efforts to diversify energy sources and mitigate climate change. Wave energy conversion (WEC) systems, as emerging technologies, offer adaptability and the potential to harness predictable wave energy. However, integration of WEC systems into a power grid brings challenges for system operators due to their nature of operation. Addressing these demands is a multilayered process that involves highly efficient power electronic devices, control systems, and efficient energy storage solutions. This paper specifically focuses on the methodologies of the grid integration of a specific wave energy conversion system—a point absorber developed by the company Sigma Energy. Proposed methodologies are experimentally tested using power hardware-in-loop (PHIL) emulation of a fully monitored and controlled small-scale microgrid equipped with a battery energy storage system (BESS), different emulators of loads, and distributed generators (DG). [ABSTRACT FROM AUTHOR]

To alleviate the energy crisis and achieve green energy conversion, the heterojunctions that can be applied to the photocatalytic decomposition of water have attracted attention. In this paper, we design a novel two-dimensional GeC/SnSe 2 heterostructure and investigate in detail the structural stability, electronic characteristics, photocatalytic activity and optical behavior as well as the effects due to the applied strain based on the first-principles. Firstly, the most stable γ-stacking mode is determined by combining energy comparison, thermodynamic and dynamic studies. Second, the analysis of electronic properties demonstrates that the GeC/SnSe 2 heterostructure exhibits a type-II energy band arrangement and a direct Z-scheme photocatalytic mechanism. This pivotal aspect enhances the separation of photogenerated carriers at the interface and facilitates the active participation of the most proficient materials in oxidation-reduction processes during photocatalytic hydrolysis reactions. The hydrolysis reaction's Gibbs free energy shift demonstrates the GeC/SnSe 2 heterostructure's superior photocatalytic activity in neutral and alkaline environments and can spontaneously carry out the overall hydrolysis reaction, and this outstanding ability is not affected by the −4% to 4% strain range. In addition, the GeC/SnSe 2 heterostructure has outstanding solar-to-hydrogen efficiency (58.18%) and excellent light absorption capability (up to 4 × 1 0 5 cm − 1 ) within visible light. The implications of these discoveries point towards the direct Z-scheme GeC/SnSe 2 heterostructure holds promise as an excellent candidate for photocatalytic water splitting applications. Free energy descriptions of the GeC/SnSe 2 heterostructure participating in water splitting (a) hydrogen evolution reaction and (b) oxygen evolution reaction under different conditions. Top and side views of the most stable adsorption sites for (c) H on the GeC layer and (d) OH, (e) O and (f) OOH on the SnSe 2 layer of the GeC/SnSe 2 heterostructure. The H and O atoms are represented by pink and red balls, respectively. [Display omitted] • The GeC/SnSe 2 heterostructure is thermodynamic, dynamic and thermal stable. • The GeC/SnSe 2 heterostructure exhibits direct Z-scheme mechanism and strong redox capacity. • Gibbs free energy diagram of water splitting demonstrates its excellent spontaneous reaction capability. • The GeC/SnSe 2 heterostructure has excellent light absorption capability within visible light. [ABSTRACT FROM AUTHOR]

Achieving low cost at high performance is difficult for direct ammonia microfluidic fuel cell (DAMFC) as a portable clean energy conversion device. In this work, a DAMFC with Ni nanoparticles anode and catalyst-free cathode is proposed to realize low cost and high performance of the fuel cell at room temperature. Due to the uniform distribution and spherical geometry of the Ni nano-catalyst, the Ni anode prepared by cyclic voltammetry owns excellent activity of ammonia oxidation. Meanwhile, sodium persulfate having strong oxidizing properties is selected as the oxidant, resulting in catalyst-free carbon paper by cyclic voltammetry treatment directly used as the cathode to greatly reduce the cost of the DAMFC. By optimizing the electrodeposition conditions of Ni electrode and the operating conditions of fuel cell, the DAMFC achieves optimal performance. The maximum power density is 8.43 mW cm−2 and the limiting current density is 78.58 mA cm−2, which is higher than that of most previously reported low-temperature ammonia fuel cells. Moreover, the fuel cell has good stability. Therefore, it proves that a DAMFC with Ni nanoparticles anode and catalyst-free cathode is an effective method to realize low cost and high performance of the ammonia fuel cell at room temperature. [Display omitted] • A low-cost and high-performance ammonia microfluidic fuel cell is proposed. • The spherical nickel nanoparticle catalyst with uniform dispersion is prepared. • Sodium persulfate with strong oxidizing property is selected as oxidant. • The effect of reactant concentration on cell performance is discussed. • The introduction of sodium persulfate removes noble-metal catalyst and improves cell performance. [ABSTRACT FROM AUTHOR]

Ocean energy sources are a promising source of energy. However, simulating a hydrokinetic farm with multiple units requires significant computational resources, while physical experimentation on site is expensive. Therefore, the scientific challenge is to develop analytical and experimental tools that consider real aspects of areas with generation potential in a controlled laboratory environment. This paper presents a theoretical and experimental tool for analysing the interconnection of a hydrokinetic energy farm comprising 20 generation units. The test bench is a Power Hardware in the Loop type, consisting of one physical prototype generator to scale and 19 discrete averaged models operating in real-time. The system allows generators to interact through an amplifier, emulating the impact of power injection in a small electrical network. This is based on the variability of the marine resource, specifically the current velocities in the Cozumel-Mexico channel. Unlike other publications, the most significant contribution of this work is a complete feasible emulation of a marine current plant interconnected to an electrical grid, where the objective is to have a global analysis of the operation of each generation unit and the impact of the interconnection as a whole, considering that such information is of utmost importance for the execution of future projects of power generation from the sea. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen reduction reaction (NRR) is a promising technology for ammonia synthesis under environmental conditions due to its simplicity of operation, high energy conversion, and environmental friendliness. While development of an efficient and stable electrocatalyst is one of the remaining key challenges. In this paper, the electrocatalytic performance of single Ru atoms anchored in Bn-doped graphyne (RuBn@GY) is systematically investigated using density functional theory (DFT) calculations. The results show that RuB@GY is a highly efficient NRR electrocatalyst with a distal and alternating mechanism considered to be the most active catalytic pathway, with a limiting potential of only − 0.53 V. Overall, our study facilitates the NRR reaction by controlling the number and position of the doped B atoms to reduce the limiting potential, and this work provides theoretical guidance for the further development of highly active and stable single-atom catalysts (SACs). Electrocatalytic nitrogen reduction reaction (NRR) is a promising technology for ammonia synthesis under environmental conditions due to its simplicity of operation, high energy conversion, and environmental friendliness. [ABSTRACT FROM AUTHOR]

Osmotic energy harvesting was a promising way to alleviate energy crisis with reverse electrodialysis (RED) membrane-based technology. Charged hydrogel combined with other materials was an effective strategy to overcome problems, including restricted functional groups and complicated fabrication, but the effect of the respective charges of the two materials combined on the membrane properties has rarely been studied in depth. Herein, a new method was proposed that charged hydrogel was equipped with charged filter paper to form dual network fiber-hydrogel membrane for osmotic energy harvesting, which had excellent ion selectivity (beyond 0.9 under high concentration gradient), high ion transference number and energy conversion efficiency (beyond 32.5% under wide range concentration gradient), good property of osmotic energy conversion (~4.84 W/m2 under 50-fold KCl and ~6.75 W/m2 under simulated sea water and river water). Moreover, the power density was attributed to the surface-space charge synergistic effect from large amounts overlapping of electric double layer (EDL), so that the transmembrane ion transport was enhanced. It might be a valid mode to extensively develop the osmotic energy harvesting. [ABSTRACT FROM AUTHOR]