Trimetallic nanoplate arrays of Ni-Fe-Mo sulfide on FeNi3 foam: A highly efficient and bifunctional electrocatalyst for overall water splitting

One of the challenges to realize large-scale water splitting is the lack of highly active and low-cost electrocatalysts for its two half reactions: hydrogen and oxygen evolution reactions (HER and OER). In this work, a Mo doping approach is adopted to enhance the HER and OER bifunctionality of NiFe-LDH. The catalyst MoNiFeSx@FeNi3 obtained after sulfidation exhibits further improved catalytic performance and good stability. In KOH solution (1.0 M), ultralow overpotentials of 67 mV and 142 mV work well to reach current densities of 10 mA cm−2 for HER and OER, separately. In urea (0.33 M) and KOH (1.0 M) solutions, catalyst urea oxidation reaction can be significantly promoted by MoNiFeSx@FeNi3, and can reach a current density of 10 mA cm−2 under the condition of 1.31 V. Most importantly, our work elaborates a facile strategy to synthesize novel trimetallic transition metal catalyst as a cut-price substitute for precious metals for highly effective overall water splitting.