PtCoNi Alloy Nanoclusters for Synergistic Catalytic Oxygen Reduction Reaction

Alloying is a viable approach to altering the local and overall structure of metallic nanocatalysts, thereby offering new possibilities to tune catalytic activities and selectivity of alloy nanoclusters. However, systematic study of the effects of alloying on the catalytic reaction mechanism is still lacking. Here, a systematic study of the oxygen reduction reaction (ORR) on the 55-atom Pt-covered alloy nanoclusters was conducted. The addition of Co atoms can not only lead to different reaction mechanism for ORR, e.g., from the hydroperoxyl dissociation to the oxygen dissociation, but also increase the catalytic activity of the Pt-covered alloy nanoclusters. The energy barrier in the reaction-determining step and the excess energy of the 55-atom Pt-covered alloy nanoclusters suggest that among the 55-atom Pt-covered bimetallic and trimetallic alloy nanoclusters, the Pt₄₂Co₁₂Ni₁ trimetallic catalyst possesses the highest catalytic activity and the best structural stability. On the basis of the "descriptor"(ΔG_OH), a series of 55-atom trimetallic clusters are predicted to exhibit excellent catalytic activities for ORR. Our comprehensive study brings new insights into the ORR mechanisms associated with various forms of alloy nanocatalysts, which may offer guidance toward future design and synthesis of more efficient and robust trimetallic alloy nanocatalysts.