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

Abstract 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 CoSe2/C nanocrystals is used, and the effect of temperature on CoSe2/C nanocrystals is studied. The morphology and catalytic properties of CoSe2/C nanocrystals annealed at different temperatures are compared in 0.5 M H2SO4. The results indicated the coralline-like CoSe2/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 H2 is nearly 98%. The outstanding HER performance of CoSe2/C-650 is due to its characteristic cora-like frame CoSe2 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.