Cation Vacancy Clusters in Ti₃C₂T<i>_x</i> MXene Induce Ultra‐Strong Interaction with Noble Metal Clusters for Efficient Electrocatalytic Hydrogen Evolution

Abstract

Abstract MXenes are promising substrates for supported noble metal electrocatalysts. Yet, it is a significant challenge to modulate the metal–support interaction (MSI) for enhancing catalytic performance. Herein, employing a facile HF etching method, the cation vacancy structures in Ti 3 C 2 T x MXenes are controllably tuned, producing nearly vacancy‐free (Ti 3 C 2 T x ‐V 0 ), single Ti atom vacancy (Ti 3 C 2 T x ‐V S ), or Ti vacancy cluster (Ti 3 C 2 T x ‐V C ) engineered MXenes. Ruthenium atomic clusters, as a model catalyst, successfully anchor on all MXene substrates. Different from the terminal O/F coordination groups on routine Ti 3 C 2 T x MXene surfaces, the Ti vacancy clusters in Ti 3 C 2 T x ‐V C create unique lattice carbon ligand environment toward Ru species, which induces ultra‐strong MSI. As a result, compared to Ti 3 C 2 T x ‐V 0 and Ti 3 C 2 T x ‐V S , the Ti 3 C 2 T x ‐V C modulated Ru clusters (Ru@Ti 3 C 2 T x ‐V C ) exhibit the optimized balance of H 2 O adsorption/dissociation and OH/H desorption, thereby delivering superior electrocatalytic performance in the alkaline hydrogen evolution reaction (HER). Within the wide range from laboratory‐level (90 mA cm −2 ) to industrial‐level (1.5 A cm −2 ) current density, Ru@Ti 3 C 2 T x ‐V C outperforms commercial Pt/C in terms of overpotential and mass activity. Moreover, as a universal substrate for noble metal catalysts, Ti 3 C 2 T x ‐V C can also anchor Ir/Pt/Rh atomic clusters and enable excellent HER catalytic activity. This work expands the scope of the MSI between MXene and noble metal catalysts.