Impact of the Coordination Environment on Atomically Dispersed Pt Catalysts for Oxygen Reduction Reaction

Because of the structural complexity and inhomogeneity, the effect of the coordination environment on the catalytic properties is underexplored in heterogeneous catalytic systems. To address this challenge, the atomically dispersed Pt is anchored on two Mo-based supports with similar morphology and particle size, that is, face-centered cubic-structured α-MoC and MoN. Spectroscopic and computational investigations demonstrate that the Pt atoms are coordinated with N atoms in Pt/MoN but with Mo atoms in Pt/α-MoC, leading to an entirely different catalytic performance in the oxygen reduction reaction (ORR). The Pt mass activity for Pt/MoN reaches 0.71 A/mgPt at 0.9 V [vs reversible hydrogen electrode (RHE)], which is 15 times higher Pt mass activity than that of Pt/α-MoC. Density functional theory calculations correlate the better ORR performance of Pt/MoN with the weaker adsorption of OH* because of the modulation of electronic properties of Pt by the coordination with N atoms. This study highlights the importance of controlling the coordination environment of metal atoms in heterogeneous (electro)catalysis and suggests that tuning the coordination environment could be an effective strategy in catalyst development.