CoSe2 nanocrystals embedded into carbon support as coralline-like catalysts for hydrogen evolution reaction

It is vital to develop a high activity, stability and inexpensive hydrogen evolution reaction (HER) catalyst for electrochemical hydrogen evolution. A high-temperature reaction approach that is Co nanocrystals on carbon support (XC-72R) and selenylation to synthetize CoSe 2 /C nanocrystals is used, and the effect of temperature on CoSe 2 /C nanocrystals is studied. The morphology and catalytic properties of CoSe 2 /C nanocrystals annealed at different temperatures are compared in 0.5 M H 2 SO 4 . The results indicated the coralline-like CoSe 2 /C-650 nanocrystals have a high performance for HER with Tafel slopes of 45.73 mV·dec −1 and onset potential of −196 mV vs. RHE. The stability maintained for at least 40 h and the Faraday Efficiency (FE) of H 2 is nearly 98%. The outstanding HER performance of CoSe 2 /C-650 is due to its characteristic cora-like frame CoSe 2 nanocrystals embedded into supernal conductive XC-72R, which not only offer affluent active reaction sites, but also boost the capacity of charge transportation in HER process.