The Ni-Mo-S Catalyst @Copper Foams with Excellent Stability and 1.5 V Drive Electrolytic Water

The development of high-efficiency, low-cost, and long-term stability catalysts for water electrolysis is significant for the sustainable production of hydrogen. The aim of this study is to reduce the overpotential and thus energy consumption. Toward this aim, transition metal sulfide catalyst (marked as S5-40 doped Ni4Mo) is successfully prepared by a fast one-step electrodeposition process on a copper foam (CF) substrate. The S-20 doped Ni4Mo/CF catalyst displays an exceedingly low overpotential of 140 and -128 mV at 10 mA cm(-2) for (oxygen evolution reaction) and (hydrogen evolution reaction), respectively. The S-20 doped Ni4Mo/CF can be powered by a commercial AA alkaline battery (1.5 V) in 1.0 m KOH. It shows a lower cell voltage of 1.595 V at 10 mA cm(-2) for overall water splitting (OWS). Up to 60 h of stability testing, compared with the S-20 doped Ni4Mo/CF catalyst before electrolysis, their performance is improved by 15.5% and 41.1% at 2 and -0.7 V versus RHE, respectively. This study offers an avenue to fabricate transition metal sulfide bi-functional catalysts for OWS and provides deep insights into the relationships among the S-doping Ni4Mo at the 1.0 m KOH electrolyte physical characterization and electrocatalytic activity.

Automated summary

This study successfully synthesized a high-efficiency, low-cost, and long-term stability catalyst for water electrolysis, which exhibited exceedingly low overpotential for both oxygen evolution reaction and hydrogen evolution reaction, as well as good stability. The research provides a new approach for the fabrication of transition metal sulfide bifunctional catalysts and offers deep insights into the relationships between the physical properties and electrocatalytic activity of S-doped Ni4Mo in the electrolyte.