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

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.