Polyelectrolyte-Induced Stereoassembly of Grain Boundary-Enriched Platinum Nanoworms on Ti3C2Tx MXene Nanosheets for Efficient Methanol Oxidation.

Abstract

Direct methanol fuel cells with high energy conversion efficiency and low hazard emissions have aroused great attention from both academic and industrial communities, but their large-scale commercial application has been blocked by high costs as well as short lifespan of the anode Pt catalysts. Here, we demonstrate a simple and scalable noncovalent strategy for the synthesis of quasi-one-dimensional (1D) Pt nanoworms grown on poly(diallyldimethyl-ammonium chloride) (PDDA)-functionalized Ti3C2Tx nanosheets as anode catalysts for methanol electrooxidation. Interestingly, the introduction of PDDA on Ti3C2Tx nanosheets can not only effectively adjust their surface charge property to strengthen the electrostatic interaction between metal and support but also induce the stereoassembly of worm-shaped Pt nanocrystals with abundant catalytically active grain boundaries, which enable the resulting hybrid to express high electrocatalytic activity, remarkable durability, and strong antipoisoning ability for methanol electrooxidation, which are better than those of the traditional Pt nanoparticle electrocatalysts loaded on carbon black, carbon nanotubes, reduced graphene oxide, and MXene matrixes. Theoretical simulations disclose that the more stable worm-shaped Pt configuration with an optimized electronic structure on the Ti3C2Tx surface possesses a weaker CO adsorption ability than that of the Pt nanoclusters, thereby providing a dramatically enhanced and sustainable electrocatalytic performance.