Ruthenium-lead oxide for acidic oxygen evolution reaction in proton exchange membrane water electrolysis

Developing an active and stable anode catalyst for the proton exchange membrane water electrolyzer(PEM-WE)is a critical objective to enhance the economic viability of green hydrogen technology.However,the expensive iridium-based electrocatalyst remains the sole practical material with industrial-level stability for the acidic oxygen evolution reaction(OER)at the anode.Ruthenium-based catalysts have been proposed as more cost-effective alternatives with improved activity,though their stability requires enhancement.The current urgent goal is to reduce costs and noble metal loading of the OER catalyst while maintaining robust activity and stability.In this study,we design a Ru-based OER catalyst incorporating Pb as a supporting element.This electrocatalyst exhibits an OER overpotential of 201 mV at 10 mA·cm^(-2),simultaneously reducing Ru noble metal loading by~40%.Normalization of the electrochemically active surface area unveils improved intrinsic activity compared to the pristine RuO_(2) catalyst.During a practical stability test in a PEM-WE setup,our developed catalyst sustains stable performance over 300 h without notable degradation,underscoring its potential for future applications as a reliable anodic catalyst.

Generation of input spectrum for electrolysis stack degradation test applied to wind power PEM hydrogen production

Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current research on the durability of proton exchange membrane electrolyzers is insufficient.Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks.In this study,the operating condition spectrum of an electrolysis stack degradation test cycle was proposed.Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference,a fluctuation output power sample set was formed.The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected.Dimensionality reduction of the operating data was performed using principal component analysis.Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm.Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example,the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed.After preliminary simulation analysis,the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack.This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy.

Layered power scheduling optimization of PV hydrogen production system considering performance attenuation of PEMEL

To analyze the additional cost caused by the performance attenuation of a proton exchange membrane electrolyzer(PEMEL)under the fluctuating input of renewable energy,this study proposes an optimization method for power scheduling in hydrogen production systems under the scenario of photovoltaic(PV)electrolysis of water.First,voltage and performance attenuation models of the PEMEL are proposed,and the degradation cost of the electrolyzer under a fluctuating input is considered.Then,the calculation of the investment and operating costs of the hydrogen production system for a typical day is based on the life cycle cost.Finally,a layered power scheduling optimization method is proposed to reasonably distribute the power of the electrolyzer and energy storage system in a hydrogen production system.In the up-layer optimization,the PV power absorbed by the hydrogen production system was optimized using MALTAB+Gurobi.In low-layer optimization,the power allocation between the PEMEL and battery energy storage system(BESS)is optimized using a non-dominated sorting genetic algorithm(NSGA-Ⅱ)combined with the firefly algorithm(FA).A better optimization result,characterized by lower degradation and total costs,was obtained using the method proposed in this study.The improved algorithm can search for a better population and obtain optimization results in fewer iterations.As a calculation example,data from a PV power station in northwest China were used for optimization,and the effectiveness and rationality of the proposed optimization method were verified.

Electrochemical impedance spectroscopy analysis to accelerate electrocatalytic system innovation

Electrochemical impedance spectroscopy(EIS)is a well-established non-destructive characterization technique for assessing the efficacy of electrochemical energy storage and conversion systems.Electrocatalytic systems based on proton exchange membrane(PEM),including PEM fuel cells and PEM water electrolyzers,play a crucial role in renewable energy conversion through electricity–hydrogen interconversion.EIS,along with its derived analysis methods—equivalent circuit model(ECM),distribution of relaxation time(DRT),and dynamic EIS(DEIS),is widely utilized to extract valuable kinetics and impedance data.The acquired information affords critical insights into processes such as mass transfer,charge transfer,and proton transfer within PEM systems.This mini review surveys the role of EIS in optimizing components and investigating operational conditions to enhance the efficiency of PEM systems.In addition,it encapsulates the principles and applications of EIS-based methods like DRT and DEIS,highlighting their potential in the practical application of PEM systems.

Corrosion Resistance of Titanium Bipolar Plate Enhanced by TiN Film

To improve the corrosion resistance of titanium(Ti)bipolar plate,titanium nitride(TiN)film was prepared on the surface of commercial TA1 pure titanium by magnetron reactive sputtering and pulse laser deposition(PLD)techniques,and the film prepared under different process parameters were evaluated.Results show that dense and complete TiN film can be obtained on TA1 surface under different preparation processes,and the corrosion current density of Ti substrate significantly increases.However,the composition of the film prepared by magnetron reactive sputtering is affected by the oxygen competition reaction,and its homogeneity is inferior to that of the film prepared by PLD.The comprehensive performance of the PLD-prepared film shows excellent characteristics in the terms of low corrosion current density(0.025μA·cm^(−2)),moderate corrosion overpotential(−0.106 V),and good hydrophobicity.

Acidic oxygen evolution reaction:Mechanism,catalyst classification,and enhancement strategies

As the most desirable hydrogen production device,the highly efficient acidic proton exchange membrane water electrolyzers(PEMWE)are severely limited by the sluggish kinetics of oxygen evolution reaction(OER)at the anode.Rutile IrO2 is a commercial acid-stable OER catalyst with poor activity and high cost,which has motivated the development of alternatives.However,hitherto most of the designed acidic OER catalysts have disadvantages of low activity or stability,which cannot meet the requirement of industrial applications.Thus,exploring suitable strategies to enhance the activity and stability of cost-effective acidic OER catalysts is crucial for developing the PEMWE technique.In this review,the main OER mechanisms,different types of catalysts,and their activity and stability characteristics are summarized and discussed,and then possible strategies to improve activity and stability are proposed.Finally,the problems and prospects of such catalysts are generalized to shed some light on the future research of advanced catalysts for acidic OER.