Simple One‐Step Molten Salt Method for Synthesizing Highly Efficient MXene‐Supported Pt Nanoalloy Electrocatalysts

Abstract MXene‐supported noble metal alloy catalysts exhibit remarkable electrocatalytic activity in various applications. However, there is no facile one‐step method for synthesizing these catalysts, because the synthesis of MXenes requires a strongly oxidizing environment and the preparation of platinum nanoalloys requires a strongly reducing environment and high temperatures. Hence, achieving coupling in one step is extremely challenging. In this paper, a straightforward one‐step molten salt method for preparing MXene‐supported platinum nanoalloy catalysts is proposed. The molten salt acts as the reaction medium to dissolve the transition metals and platinum ions at high temperatures. Transition metal ions oxidize the A‐site element from its MAX precursor at high temperatures, and the resulting transition metals further reduce platinum ions to form alloys. By coupling Al oxidation and platinum ion reduction using a molten salt solvent, this method directly converts Ti 3 AlC 2 to a Pt‐M@Ti 3 C 2 T x catalyst (where M denotes the transition metal). It further offers the possibility of extending the Pt‐M phase to binary, ternary, or quaternary platinum‐containing nanoalloys and converting the Al‐containing MAX phase to Ti 2 AlC and Ti 3 AlCN. Due to the strong interfacial interaction, the as‐prepared Pt‐Co@Ti 3 C 2 T x is superior to commercial Pt/C (20 wt.%) in the hydrogen evolution reaction.