Reparation And Electrocatalytic Performance Of Selenium-Modified Ruthenium-Based Catalysts

Energy plays an important role in human life.Hydrogen has been considered as the most promising energy source to replace fossil fuels.Proton exchange membrane water electrolyzers hold practical promise for green hydrogen production due to high current density,energy efficiency,and safety.However,the complex process and slow kinetics of the oxygen evolution reaction(OER)at the anode side currently limit the overall electrochemical system efficiency.Ruthenium(Ru)-based materials are considered to be ideal OER catalysts in the future due to their superior activity and low price.However,due to the structural instability of Rubased materials during the OER process,large-scale applications cannot be achieved.Based on the above understanding,this paper develops a simple and convenient method to introduce non-metal element selenium(Se)into Ru-based materials through process improvement and structure regulation,and prepares a series of Se-modified Ru-based nanocomposites.In the first work of this paper,we proposed a strategy combining ball milling and annealing process for the realization of selenium-assisted synthesis of RuOxSey high-efficiency composite catalysts.The catalyst prepared at 800℃ has optimized micro-morphology and phase composition,and exhibits excellent OER activity in acidic electrolytes,with an overpotential of only 211 mV at a current density of 10 mA cm-2,and a fast the reaction kinetics and long-term working stability of more than 18 h are superior to commercial RuO2 and most similar catalysts reported in literature.This work is expected to be used for the large-scale preparation of metal oxide composite catalysts doped with various nonmetal elements,and to expand its application in the field of energy catalysis.In the second work of this paper,we report a facile selenium-assisted reduction method for the preparation of partially reduced nanoscale Ru directly from commercial RuO2 by a ball milling and annealing process with immobilization of mixed-valence Se species.The obtained Ru/SeRuO2 composites exhibit excellent electrocatalytic performance towards acidic OER with an overpotential of 190 and 240 mV at 10 and 100 mA cm-2.respectively,and a Tafel slope of only 43.7 mV dec-1,and show excellent stability after 24 h chrono-potential testing.The experimental results further demonstrate that the synergistic effect of Ru/RuO2 heterostructure enhances the electron transfer interactions,while the doping of selenium helps to generate more available catalytically active sites.Theoretical calculations show that a small amount of Se doping and metallic Ru loading can significantly reduce the free energy change of*OOH intermediate formation and thus significantly improve the OER performance.This strategy provides a promising strategy for the development of high-performance catalysts modified with non-metallic elements and related hydroelectric catalytic devices for sustainable energy applications.