MXene Analogue: A 2D Nitridene Solid Solution for High‐Rate Hydrogen Production

A new MXene analogue, V-Mo-based 2D layered transition metal nitride solid solution (V0.2Mo0.8N1.2), was synthesized via a catalytic molten-salt method. It exhibited excellent activity and stability for hydrogen evolution reaction, superior to most MXenes. Boosted electrocatalytic performance originates from an optimized electronic structure induced by V atom alloying. Electrocatalysts for high-rate hydrogen evolution reaction (HER) are crucial to clean fuel production. Nitrogen-rich 2D transition metal nitride, designated “nitridene”, has shown promising HER performance because of its unique physical/chemical properties. However, its synthesis is hindered by the sluggish growth kinetics. Here for the first time using a catalytic molten-salt method, we facilely synthesized a V−Mo bimetallic nitridene solid solution, V0.2Mo0.8N1.2, with tunable electrocatalytic property. The molten-salt synthesis reduces the growth barrier of V₀.₂Mo₀.₈N₁.₂ and facilitates V dissolution via a monomer assembly, as confirmed by synchrotron spectroscopy and ex situ electron microscopy. Furthermore, by merging computational simulations, we confirm that the V doping leads to an optimized electronic structure for fast protons coupling to produce hydrogen. These findings offer a quantitative engineering strategy for developing analogues of MXenes for clean energy conversions. Refereed/Peer-reviewed