Spatial Configuration Modulation of 2D Pd‐Pt Heterostructures for Boosting Electrochemical Oxygen Reduction

Abstract 2D metal heterostructures have shown great promise as highly efficient catalysts. However, how the spatial configuration of distinct components within 2D metal heterostructures affects their electrocatalytic performance still remains unclear. Herein, the controlled construction of Pd‐Pt heterostructures with two distinct spatial configurations are reported, i.e., novel lateral heterostructure and conventional core–shell structure, through different epitaxial growth modes. Specifically, Pd‐Pt mesoporous nanosheets (Pd‐Pt MNSs) with abundant exposed Pd‐Pt planar interfaces are prepared through the in‐plane lateral epitaxial growth of Pt on Pd mesoporous nanosheets (Pd MNSs) by using carbon monoxide (CO) as a capping agent, which can selectively cover the (111) basal plane of Pd MNSs to inhibit the Pt growth on the basal planes, while Pd@Pt core–shell mesoporous nanosheets (Pd@Pt MNSs) are obtained without CO. Impressively, the obtained Pd‐Pt MNSs exhibit excellent catalytic performance for oxygen reduction reaction (ORR) in alkaline media, outperforming the Pd@Pt MNSs and commercial Pd/C. Density functional theory calculations demonstrate that the exposed Pd‐Pt planar interface in Pd‐Pt MNSs possesses the preferential adsorption of reaction intermediates, demonstrating a reduced energy barrier in ORR compared to individual Pd and Pt sites. This work highlights the critical role of engineering the spatial configuration in metal heterostructures for efficient electrocatalysis.