A Supported Metal Dual-Atom Site Catalyst for Oxygen Reduction: A First-Principles Study

Dual-atom site catalysts with the adjacent metal atomic sites can cooperatively catalyze oxygen reduction reaction (ORR), showing great potential in ORR field. Herein, the ORR activity and mechanism of a supported metal dual-atom site catalyst M₂-DAC (M is 3d transition metal) is explored thoroughly by density functional theory methods. By calculating E_d of M₂-DAC, all structures are thermodynamically stable and are used for subsequent studies. Considering the adsorption of O₂, total 6 kinds of M₂-DAC are identified as potential candidate materials for catalyzing ORR due to their moderate adsorption of O_2. The binding energy of ORR species and the change of Gibbs free energy in each step of ORR are calculated, and Co₂-DAC exhibits notable catalytic activity (η^ORR = 0.39 V). Moreover, the charge analysis of Co₂-DAC shows that the ORR activity of the catalyst mainly comes from the metal atom and the O atoms coordinated with the metal atoms.