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

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, V Mo N , with tunable electrocatalytic property. The molten-salt synthesis reduces the growth barrier of V Mo N 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.