Synthesis And Oxygen Evolution Properties Of Selenium Telluride Based On Structure Regulation

As an energy carrier with high energy density,hydrogen energy is of great strategic significance for alleviating energy and environmental problems in various countries and accelerating energy conservation and emission reduction.Among the many hydrogen production technologies,the hydrogen production technology of electrolyzed water with high conversion rate and environmental friendliness has received widespread attention.Hydrogen production from electrolyzed water is composed of oxygen evolution reaction and hydrogen evolution reaction,among which the thermodynamic overpotential of the anode oxygen evolution reaction is high and the kinetic mass transfer is slow,which limits the development of electrolyzed water technology.Therefore,the development of economical,efficient,durable and stable oxygen evolution catalysts is the focus of research to improve the energy conversion efficiency of electrolyzed water.Compared with oxygen evolution catalysts such as transition metal oxides and sulfides,transition metal selenium telluride catalysts have more unique advantages in electrical conductivity and stability.Based on the research ideas of"geometry and morphology of electronegative differential regulation catalysts"and"two-element co-effect modification of substrate electronic structure",a series of transition metal selenium telluride oxygen evolution catalysts were prepared on nickel foam substrates by combining hydrothermal method,calcination and ion exchange synthesis methods,and the rational design and performance of oxygen evolution catalysts were realized by adjusting the catalyst structure,increasing the active site and improving the conductivity,and the main research contents were as follows:（1）Preparation of Te-NiSe-Ni₃Se₂/NF catalyst.Based on the research idea of differential electronegativity to regulate the structure and morphology of catalysts,Te and Se elements with similar outer electron arrangement structures but obvious differences in electronegativity were selected,and Na₂Te O₃ was used as the Te source,N₂H₄·H₂O was used as the reducing agent,and Te-NiSe-Ni₃Se₂/NF catalyst with unique coral-like structure was prepared by one-step hydrothermal method.It is found that Te with weak electronegativity is beneficial for cutting off the bonding between Ni-Se,forming more marginal active site structures and increasing the active area of the reaction.Se facilitates the successive"coral network"structure and improves the stability of the catalyst.After activity tests,Te-NiSe-Ni₃Se₂/NF catalyst had excellent catalytic performance(?₁₀=293m V)in 1 M KOH electrolyte,with a small Tafel slope(81 m V dec^-1)and the current density of the catalyst did not attenuate after 12 h i-t stability test.（2）Preparation of NiTe₂/NF@CuFe catalyst.Based on the research idea that iron and copper can regulate the electronic structure of foam nickel,high efficient oxygen evolution reaction catalyst NiTe₂/NF@CuFe was synthesized through a simple displacement hydrothermal combination strategy.The doping of Cu produces a cutoff zone that effectively controls the morphology of the catalyst.The introduction of Fe increases the stability of the catalyst structure,making the NiTe₂/NF@CuFe catalyst perform well during oxygen evolution reaction.The NiTe₂/NF@CuFe catalyst exhibits extremely low overpotential(?₁₀=228 m V)under alkaline conditions（1 M KOH）,the Tafel slope was as low as 33 m V dec^-1.Compared to the control group without Cu and Fe doping,the catalyst was very stable during the 12 h oxygen evolution reaction catalytic process.The calculation results show that Cu atoms not only promote the charge transfer process,but also establish independent regions of NiTe₂ nanoparticles.Fe atoms increase the anchoring effect between NiTe₂ nanoparticles and the substrate,stabilize the catalyst structure,and improve electronic activity.