Nickel hydroxide armour promoted CoP nanowires for alkaline hydrogen evolution at large current density

The development of hydrogen evolution activity (HER) electrocatalyst that can run durably and efficiently under the large current density is of special significance but still chal-lengeable for the massive production of hydrogen. Herein, a CoP/Ni(OH)(2) nanowire cata-lysts grown on Co foam (CF) with a three-dimensional heterojunction structure has been successfully prepared by electrodepositing nickel hydroxide on the surface of cobalt phosphide. The prepared CoP/Ni(OH)(2)-15 min sample reveals a superior HER activity and stability. It merely requires ultralow overpotentials of 108 and 175 mV to 100 and 500 mA cm(-2), respectively. In addition, the long-term stability test shows that the catalyst (CoP/Ni(OH)(2)-15 min) can operate stably for at least 70 h at 400 mA cm(-2). Utilizing NiFeLDH/IF with high OER activity, the NiFe-LDH/IF parallel to CoP/Ni(OH)(2)-15 min catalyst system possesses the same outstanding performance for overall water splitting (OWS), which can accomplish z 500 mA cm(-2) at 1.74 V in 1 M KOH electrolyte. Moreover, the NiFe-LDH/IF parallel to CoP/Ni(OH)(2)-15 min couple can work for more than 80 h at 500 mA cm(-2), indicating its a great prospect in the area of electrolysis water. Such excellent catalytic performance is mainly attributed to the armor effect of Ni(OH)(2), which can not only promote the rapid decomposition of water molecules, but also prevent the loss of phosphorus and enhance the synergistic effect of CoP and Ni(OH)(2). This work can offer a significant reference for the design with high-performance and durable transition metal phosphide electrocatalysts. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.