Hierarchical CoNiSe₂ nano-architecture as a high-performance electrocatalyst for water splitting

Hierarchical nano-architectures comprised of ultrathin ternary selenide (CoNiSe₂) nanorods were directly grown on nickel foam (NF). The integrated CoNiSe₂/NF functions as a robust electrocatalyst with an extremely high activity and stability for emerging renewable energy technologies, and electrochemical oxygen and hydrogen evolution reactions (OER and HER, respectively). The overpotentials required to deliver a current density of 100 mA·cm^-2 are as low as 307 and 170 mV for the OER and HER, respectively; therefore, the obtained CoNiSe₂ is among the most promising earth-abundant catalysts for water splitting. Furthermore, our synthetic sample validates a two-electrode electrolyzer for reducing the cell voltage in the full water splitting reaction to 1.591 V to achieve a current density of 10 mA·cm^-2, which offers a novel, inexpensive, integrated selenide/NF electrode for electrocatalytic applications.