Superior Electrocatalyst for All-pH Hydrogen Evolution Reaction: Heterogeneous Rh/N and S Co-Doped Carbon Yolk-Shell Nanospheres

Design of efficient and robust electrocatalysts for hydrogen evolution reaction (HER) under all pH conditions has attracted significant attention. In particular, it is still a considerable challenge since the HER kinetics of Pt in alkaline solutions is about two to three orders of magnitude lower than that in acidic conditions. Herein, a heterogeneous yolk-shell nanostructure with Rh nanoparticles embedded in S, N co-doped carbon nanospheres prepared by a facile self-template method is reported. The optimized electrocatalyst can achieve an extremely small overpotential of 13.5 mV at 10 mA cm(-2), low Tafel slope of 25.5 mV dec(-1), high turnover frequency of 0.143 s(-1) (at -75 mV vs. reversible hydrogen electrode), and long-term durability for 10 h, which is the record-high alkaline HER activity among the ever-reported noble metal based catalysts. These striking performances are ascribed to the optimized electronic structure and unique heterogeneous yolk-shell nanostructure. More importantly, it is also demonstrated that the obtained electrocatalyst exhibits superior activities in all pH range, which is better than commercial Pt/C and Rh/C catalysts. This work proves that Rh-based nanomaterials are promising superior electrocatalysts in a wide pH range and nanostructure design is a powerful tool to increase the mass/electron transfer during reaction.