Theoretical Study Of The Adsorption Properties And Oxygen Reduction Reaction On New Two-Dimensional Materials

The rapid development of society has brought about problems such as energy consumption and gas pollution,prompting people to search for new energy and gas sensing materials.In this paper,based on first-principles density functional theory,the adsorption characteristics of oxygen reduction reaction(ORR)intermediates(O,OH,O2,H2O2,H2O)and the oxygen reduction reaction process on intrinsic bismuthene,graphene/bismuthene heterojunction have been studied.The adsorption characteristics of CO and H2S gas molecules on intrinsic antimonene,Co and Ni modified antimonene have been studied.The results show that:(1)The adsorption energies of ORR intermediates on intrinsic bismuthene and graphene/bismuthene heterojunction are linear;The adsorption energies of O2 and OOH on intrinsic bismuthene are 2.08eV and 1.94eV,which are strong and conducive to the breaking of O-O bond in O2 and OOH.The adsorption energy of graphene/bismuthene heterojunction on OH is small,which is conducive to the reaction of OH and H atoms to form H2O.The adsorption energy for H2O is-0.64eV,which is beneficial to the desorption of H2O;On the graphene/bismuthene heterojunction,the ORR intermediate is subjected to the localized interaction and the synergistic effect of the graphene layer and the bismuthene layer,and the adsorption energy of ORR intermediate is lower than that of the intrinsic bismuthene.(2)Both two-electron and four-electron processes exist on the intrinsic bismuthene,and only four-electron processes exist on the graphene/bismuthene heterojunction.The free energy of each step of ORR reaction on intrinsic bismuthene is less than zero,indicating that ORR has a tendency of spontaneous reaction on intrinsic bismuthene.In the heterojunction,the change of free energy at the third step is more uniform except that the change value of free energy at the third step is positive.These results indicate that the intrinsic bismuthene and graphene/bismuthene heterojunction structures exhibit certain catalytic activity for ORR,and they can be used as potential new catalyst materials for ORR.(3)The adsorption energy of CO and H2S on intrinsic antimonene is 0.19eV and 0.17eV,respectively,which indicates that intrinsic antimonene is insensitive to CO and H2S.The adsorption energies of CO on Co and Ni modified antimonene are 2.19eV and 2.06eV,respectively.The adsorption energies of H2S on Co and Ni modified antimonene were 0.94eV and 1.05eV,respectively.The modification of Co and Ni atoms can improve the adsorption of Co and H2S by antimonene obviously.The changes of adsorption energy,charge transfer after adsorption and band gap showed that the adsorption of Co and Ni atoms on antimonene was significantly higher than that of H2S molecules.The results indicate that Co and Ni modified antimonene is more sensitive to CO gas molecules and has higher selectivity to CO gas.Co and Ni atoms modified antimonene can be used as a new gas sensing material for CO molecular sensor.