V-Shaped RuO2 Nanotwin Complex Defect Facilitation of OER Reaction

RuO2 is one of the most active catalysts for the acidic oxygen evolution reaction (OER). As a first step in understanding the mechanism for V-shaped RuO2 nanotwin facilitation of the OER reaction, the relaxed atomic configuration and detailed partial density of states are determined using density-functional theory and are shown to dictate an upward shift of d- and p-band centers. The RuO2 101-nanotwin grain boundary (101-TGB), as the first ∑101 V-shaped structure constructed, reduces the distance between kinked Ru and its surrounding O atoms, which enhances p–d hybridization. The special structure properly regulates the value of ΔG*O–ΔG*OH and charge-transfer energy. In addition, with the introduction of transition-metal and oxygen vacancies, the degree of nanotwin dislocation increases, exhibiting positive effects on the improvement of surface catalytic activity. Regulating the synergistic effect of nanotwins and transition metals can thus be crucial in assisting the exploration of new, multiple, and excellent RuO2-based nanocatalyst materials.