Ru‐Anchored Vacancy‐Engineered Nitrogen‐Doped Ti 3 C 2 T x MXene Nanoribbons for Photothermal‐Driven Efficient Hydrogen Generation and Solar Water Evaporation

ABSTRACT 2D MXenes with their tunable surface terminations and high conductivity offer considerable promise for electrocatalytic applications. However, uncontrolled surface defects and functional groups formed during chemical etching compromise their intrinsic metallic nature and weaken electronic metal‐support interactions (EMSI) with anchored noble metals. Herein, a rational strategy is developed by constructing oxygen‐vacancy (OV) modulated, N‐doped 1D Ti 3 C 2 T x MXene nanoribbons anchored with ultrasmall Ru atomic clusters (Ru@N–Ti 3 C 2 T x NRs) for efficient hydrogen generation and solar water evaporation. The resulting composite exhibits exceptional hydrogen evolution reaction (HER) activity, requiring exceptionally low overpotentials of only 12 mV (22 mV) under light (dark) conditions at 10 mA cm −2 , with Tafel slopes of 34 mV dec −1 (50 mV dec −1 ), outperforming commercial Pt/C. Density functional theory calculations reveal that OV modulation tailors the electronic structure, optimizes the hydrogen adsorption free energy, and enhances the EMSI. We further show that under light irradiation, photothermal/photochemical effects and accelerated charge transfer synergistically boost the HER kinetics. Benefiting from its photothermal properties, a 3D Janus evaporator constructed from Ru@N‐Ti 3 C 2 T x NRs achieves a high solar‐driven water evaporation rate of ∼3.2 kg m −2 h −1 with excellent long‐term stability. This study paves the way to develop a 1D MXene‐based platform for clean hydrogen production and solar desalination by combining defect engineering, heteroatom doping, and noble metal anchoring.