Mo-doped cobalt hydroxide nanosheets coupled with cobalt phosphide nanoarrays as bifunctional catalyst for efficient and high-stability overall water splitting

Abstract

Exploring earth-abundant bifunctional electrocatalysts with highly efficient activity for overall water splitting is exceedingly challenging. Herein, a facile electrodeposit-phosphating-electrodeposit strategy is developed to obtain Mo-doped Co(OH) 2 nanofilms coupled with CoP nanosheets loaded on nickel foam (denoted as MoCo(OH) 2 /CoP/NF). Benefitting from the unique structural merits, MoCo(OH) 2 /CoP/NF exhibits outstanding electrocatalytic performance both for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The results indicate that the dopant of Mo in the Co(OH) 2 can further improve the electrocatalytic performance. To achieve a current density of 10 mA cm −2 , only 15 and 287 mV are required for HER and OER in 1 M KOH solution, respectively. When MoCo(OH) 2 /CoP/NF simultaneously employed as cathode and anode for overall water splitting, it only requires 1.593 and 1.853 V to achieve 10 and 50 mA cm −2 , respectively. The electrocatalytic activity of MoCo(OH) 2 /CoP/NF for overall water splitting even exceed the benchmark electrode couple of Pt/C/NF||RuO 2 /NF, and MoCo(OH) 2 /CoP/NF perform excellent durability for overall water splitting. This work opens up new avenues for large-scale commercial production of overall water splitting catalysts due to its low-cost and facile method. • MoCo(OH) 2 /CoP/NF was synthesized via facile and low-cost electrodeposit-phosphating-electrodeposit strategy. • The dopant of Mo in α-Co(OH) 2 could effectively improve the HER and OER activity in alkaline solution. • The MoCo(OH) 2 /CoP/NF bifunctional electrocatalyst exhibits excellent activity and stability for overall water splitting.