CoP@NC nanorod array for efficient alkaline water and alkaline seawater electrolysis

Seawater electrolysis to produce hydrogen and oxygen is an attractive candidate for renewable energy, but bottlenecks still remain to develop efficient and stable electrocatalysts. Herein, the N-doped carbon enveloped CoP hierarchical core-shell structured nanoarray is fabricated on carbon fiber cloth through a controllable approach. Scanning electron microscope and transmission electron microscope reveal the nanoarray architecture and core-shell structure of CoP@NC. When tested as bifunctional catalysts toward water electrolysis, the sample demonstrates efficient catalysis performances with low HER overpotentials of 136/139 mV and OER overpotentials of 238/244 mV to generate a current density of 100 mA cm −2 in alkaline water/seawater, respectively. The two-electrode system of CoP@NC/CC= |CoP@NC/CC needs low cell voltage of 1.68 V to yield 100 mA cm −2 in alkaline seawater, which can maintain the performance for over 100 h. The charming hierarchical core-shell structure, appropriate components, and specific nanoarray morphology are synergistically responsible for the good electrocatalysis performances.