Boosting interfacial charge transfer for alkaline hydrogen evolution via rational interior Se modification

For electrocatalytic hydrogen evolution reaction (HER) in alkaline media, it is urgently needed to accelerate the generation of H*. Here, using Se doped phosphides inside nitrogen doped carbon (skin-core structure) as catalysts, the HER performance in alkaline electrolyte was improved. The overpotential of 261 mV at 400 mA cm−2 was among the top level reported so far. Based on the combination of experimental results and density functional theory (DFT) calculations, the interior CoSe phase generated by Se modification provides faster charge transfer from the inner to carbon layer, facilitating the rate-determining step (Volmer). Also, the needle-like nanowire array facilitates the H2 desorption at a large current density. Furthermore, a solar-to-hydrogen efficiency up to 10.2% was demonstrated. This work may provide an effective strategy to boost the reaction kinetics via accelerating interfacial charge transfer ability of electrocatalysts.