PtCo@NCs with Short Heteroatom Active Site Distance for Enhanced Catalytic Properties

Abstract The crucial issue for fuel cells is to improve the activity and durability of Pt‐based catalysts. Herein, based on the short distance enhancement effects, a novel PtCo@NC catalyst with remarkably enhanced electrocatalytic properties for methanol oxidation reaction (MOR) in acidic electrolytes is developed by shortening the Pt–Co active site distance. In brief, a series of PtCo@NC catalysts with different Pt–Co biatomic arrangement are precisely synthesized by an in situ reduction‐fusion method, achieving Pt–Co structural evolution from a Pt/Co individual monometallic islet (A‐700 °C) to PtCo heterodimer (A‐800 °C) and then a PtCo alloy (A‐900 °C) embedded on nitrogen‐doped carbon matrixes. Compared with the Pt/Co monometallic islet and heterodimer, the PtCo@NC (A‐900 °C) with the shortest Pt–Co active site distance exhibits the highest mass activity of 2.30 A mg Pt −1 , which is 12.23 times higher than that of commercial Pt/C and exceeds almost all the reported MOR catalysts in acidic electrolytes. Both experiments and density functional theory calculations reveal that the remarkably improved activity stems from the modification of electron distribution around Pt/Co metal centers, thus promoting the rate‐determining methanol dehydrogenation step and CO oxidative removal processes, which are dependent on the distance between bimetallic active sites.