Surface engineering of RhOOH nanosheets promotes hydrogen evolution in alkaline

Hydrogen evolution reaction (HER), a promising strategy for converting electricity to value-added H2 fuel, is a key half reaction of the overall water splitting. However, HER is suffering from the sluggish kinetics in alkaline. We here demonstrate a highly efficient catalyst for alkaline HER via surface and interface engineering of RhOOH nanosheets (NSs). The surface structure of RhOOH NSs can be precisely tuned by altering the cyclic voltammogram cycles (CVs) in the activation process, leading to the formation of strongly synergized RhOOH/Rh interface for boosted HER activity in alkaline. The optimized catalyst exhibits a promising alkaline HER performance with overpotential of 18 mV at current density of 10 mA∙cm−2 and Tafel slope of 19.3 mV∙dec−1 in 1 M KOH, which surpasses the commercial Pt/C, Rh NSs/C and RhOOH NSs/C. Detailed experiments and theoretical calculations reveal that the synergy between RhOOH and Rh significantly promotes the H2O adsorption/dissociation to form Had and the Had desorption to produce H2.