Adsorption properties of the intermediates of oxygen reduction reaction on bismuthene and graphene/bismuthene heterojunction based on DFT study

The adsorption properties of the intermediates of oxygen reduction reaction on bismuthene and graphene/bismuthene heterojunctions have been studied, and the oxygen reduction reaction processes have been simulated. The five intermediates, O, OH, O 2 , OOH and H 2 O, all tend to adsorb on the vacancy sites of the bismuthene, with adsorption energies of − 4.42 eV, − 3.48 eV, − 2.08 eV, − 1.94 eV and − 0.25 Ev, respectively. The adsorption energies of intermediates adsorbed on the bismuthene side in the heterojunction interspace decrease to − 4.31 eV, − 3.15 eV, − 1.60 eV, − 0.93 eV and 0.64 eV, respectively, resulting from space confinement effect. For oxygen reduction reaction, both bismuthene and graphene/bismuthene heterojunction show certain catalytic activity. The free energy changes of each step are negative, showing a spontaneous trend of reaction on the bismuthene. While both two-electron and four-electron processes exist on the bismuthene, there are solely four-electron processes that exist on the heterojunction, avoiding the production of H 2 O 2 which is detrimental to the catalyst and the proton exchange membrane.