Engineering Support and Distribution of Palladium and Tin on MXene with Modulation of the d‐Band Center for CO‐resilient Methanol Oxidation

Abstract

AbstractThe efficiency of direct methanol fuel cell (DMFC) is largely determined by the activity and durability of methanol oxidation reaction (MOR) catalysts. Herein, we present a CO‐resilient MOR catalyst of palladium‐tin nano‐alloy anchored on Se‐doped MXene (PdSn0.5/Se−Ti3C2) via a progressive one‐step electrochemical deposition strategy. MOR mass activity resulting from Pd/Se−Ti3C2 catalyst (1046.2 mA mg−1) is over 2‐fold larger than that of Pd/Ti3C2, suggesting that the introduction of Se atoms on MXene might accelerate the reaction kinetics. PdSn0.5/Se−Ti3C2 with Se‐doping progress of MXene and the cooperated Pd−Sn sites has a superior MOR mass activity (4762.8 mA mg−1), outperforming many other reported Pd‐based catalysts. Both experimental results and theoretical calculation reveal that boosted electron interaction of metal crystals with Se‐doped MXene and optimized distribution of Pd−Sn sites can modulate the d band center, reduce adsorption energies of CO* at Pd site and enhance OH* generation at Sn site, resulting in highly efficient removal of CO intermediates by reaction with neighboring OH species on adjacent Sn sites.