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, O2, OOH and H2O, 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 H2O2 which is detrimental to the catalyst and the proton exchange membrane.