Theoretical Investigation On The Electrocatalysis Properties Of Mxene-based Catalysts

Environmental pollution and energy crisis are two major problems in today’s world,so people need to find clean,pollution-free renewable energy urgently.The proton exchange membrane fuel cells(PEMFCs)are the clean energy conversion device that converts chemical energy into electrical energy.The theoretical design of PEMFC electrode catalysts is extremely important to improve the increasingly serious environmental problems.The traditional platinum/carbon catalysts have the problems that platinum is difficult to resist carbon monoxide poisoning,carbon black is easily corroded,the catalyst is expensive,and the kinetics of the oxygen reduction reaction(ORR)is slow.In order to solve these problems,this paper performs theoretical studies using the first-principles calculations based on density functional theory.Firstly,the applications of MXenes in the electrocatalysis field(mainly in CO oxidation and ORR)are reviewed We find that the MXenes are the good substrate materials for catalyzing CO oxidation and ORR.Then we perform theoretical research on the ORR activity of subnano clusters supported on MXenes,which provides theoretical guidance for the MXene-based electrocatalvsts.We hope that the results of this study can provide theoretical support for the design and development of efficient and stable MXene-based catalysts.The detailed researching contents are summarized as follows1.MXenes as the support of catalysts for the CO oxidation and ORRThe structure,preparation and electrocatalytic performance of MXenes are systemitically reviewed.In order to provide guidelines for experimental and theoretical researches,we summarized the potential applications of MXenes in catalysis from the view of both theoretical and experimental investigations,especially the recent progress of titanium carbide and molybdenum carbide MXenes for CO oxidation and ORR catalysts.The results show that MXenes are the good substrate material,and their compositing with metal atoms,metal nanoparticles,metal monolayers,or some other two-dimensional materials may adjust the performance of electrocatalysts for CO oxidation and ORR performance2.The Ptn(n=1-4)and Pt3Au subnano clusters supported on Ti2CO2 MXenes for ORRThe adsorption properties,electronic structure,and ORR activity of Ptn(n=1-4)and Pt3Au subnano clusters supported on Ti2CO2 are investigated.In order to reduce the amount of precious metal platinum and increase the kinetics of ORR for the electrocatalysts,and to understand the ORR catalytic activity induced by platinum alloys,we study the influence of different platinum amount and doping foreign metals on Ti2CO2 substrates on the ORR catalytic activity.The results show that the Pt3Au subnano clusters form a stable 3D structure on the Ti2CO2 and possess excellent ORR activity(the catalysts’ oxygen reduction activity is significantly enhanced by introducing the transition metal Au with higher electronegativity and richer d electrons).We hope that this research would promote the design and development of ORR catalysts and provide a theoretical reference for the rational design of transition metal subnano clusters and MXenes composite catalysts.