Supercritical CO2 etching MXene for RuSe2 coating as high-efficiency alkaline hydrogen evolution reaction catalyst

Alkaline water electrolysis poses significant potential for large-scale industrial hydrogen generation, but is impeded by the absence of an efficient electrocatalyst capable of operating at high current densities while maintaining with minimal overpotential. Herein, we construct a mechanically stable and highly active RuSe₂/MXene heterojunction electrocatalyst. A typical SC-Ti₃C₂T_x MXene substrate was successfully prepared by supercritical CO₂ (SC-CO₂) etching, combined by subsequent DMSO intercalation treatment. Further, the RuSe₂ nanoparticles were uniformly deposited on the surface of SC-Ti₃C₂T_x. Theoretical calculations and experimental results demonstrate that fluorine-rich MXene exhibits stable binding with the active 1T phase RuSe₂. The as-prepared representative RuSe₂@SC-Ti₃C₂T_x-3 heterostructure showed exceptional alkaline hydrogen evolution performance, demonstrating an overpotential of 15 mV at 10 mA cm⁻² and a Tafel slope of 21.84 mV dec⁻¹, which presents excellent HER performance and stability at high-current-density conditions. Moreover, the overpotential under the current density of 500 mA cm⁻² is merely 182 mV, and the HER efficiency remains unaffected even after 5000 cycles and 120 h of continuous testing.

Graphical abstract

A novel protocol is proposed for etching Ti3AlC2 MAX phase depending on the supercritical CO2 and ZnF2·4H₂O as an effective etchant to fabricate MXene with enriched F delamination. The F-rich MXene exhibits stronger interactions with the active 1T phase RuSe2, thereby significantly enhancing the electrocatalytic activity and stability under high current density.