Ruthenium single‐atom modulated Ti₃C₂T_x MXene for efficient alkaline electrocatalytic hydrogen production

Abstract Single‐atoms (SAs) supported on various substrates have emerged as a new form of electrocatalysts for hydrogen evolution reaction (HER). The exfoliated MXenes possess rich defects/vacancies and surface oxygen groups, can be favorably utilized to anchor SAs. Here, we take advantage of the exfoliated Ti₃C₂T_x to anchor Ru‐SAs on Ti₃C₂T_x through a wet‐chemistry impregnation process. The obtained Ru_SA@Ti₃C₂T_x possesses excellent HER activity, especially under high current densities. Remarkably, Ru_SA@Ti₃C₂T_x can readily attain high current densities of 1 and 1.5 A cm⁻² at low over potentials of 425.7 and 464.6 mV, respectively, demonstrating its potential for practical applications. The A_1g vibration frequency shift of the Raman spectrum is innovatively used to probe the surface OH coverage on Ti₃C₂T_x, providing critical information for mechanistic studies. The experimental and theoretical studies reveal that the superior HER electrocatalytic activity of Ru_SA@Ti₃C₂T_x results from the Ru‐SAs enhanced H₂O adsorption and dissociation, and promoted H₂ formation.image