Construction of RuO₂/TiO₂-Ti₃C₂T_x alkaline hydrogen oxidation catalyst and its high CO tolerance

The slow kinetics of hydrogen oxidation reaction (HOR) in alkaline medium greatly restricts the development of hydrogen oxygen fuel cells. Therefore, the development of high-performance alkaline HOR catalysts has become the main task nowadays. RuO₂/TiO₂-Ti₃C₂T_x catalyst was synthesized in one step by hydrothermal method using two-dimensional Ti₃C₂T_x MXene as catalyst carrier. The surface morphology and electronic structure of the catalyst were first characterized in detail by TEM, XRD and XPS. Then, it was found by electrochemical test that RuO₂/TiO₂-Ti₃C₂T_x showed excellent HOR activity in 0.1 mol/L KOH electrolyte: At 50 mV overpotential (vs. RHE), RuO₂/TiO₂-Ti₃C₂T_x exhibits a high geometric exchange current density (j₀) of 1.58 mA·cm⁻² and geometric dynamic current density (j_k) of 17.06 mA·cm⁻², which is 4.77 times than that of Pt/C catalyst. In addition, in the hydrothermal reaction process, part of Ti₃C₂T_x MXene catalyzes the surface oxidation of the carrier to form TiO₂, so that RuO₂/TiO₂-Ti₃C₂T_x can run continuously for 5000 s under the condition of 0.1% CO, and still show stable electrocatalytic HOR performance. The catalytic carrier Ti₃C₂T_x MXene regulates the electronic structure of the active metal Ru, which further reduces the hydrogen binding energy (HBE) at the active site. RuO₂/TiO₂-Ti₃C₂T_x showed better HOR properties than commercial Pt/C and Ru/C catalysts with enhanced hydroxyl binding energy (OHBE). This study provides a new strategy for the design and development of highly active and stable alkaline HOR electrocatalysts.