Construction of Mo doped CoMoCH–Cu2SeS/NF composite electrocatalyst with high catalytic activity and corrosion resistance in seawater electrolysis: A case study on cleaner energy

Abstract

The electrolysis of seawater into clean hydrogen energy requires the development of effective electrocatalysts. Yet, most current research focuses on the activity of electrocatalysts while disregarding their corrosion resistance. We developed a unique porous stake-like composite catalyst on a nickel foam substrate (designated by CoMoCH–Cu2SeS/NF) using a new monometallic cation release method, demonstrating an outstanding catalytic activity and a high resistance to seawater corrosion. CoMoCH–Cu2SeS/NF porous stake-like structure provides a large reaction zone and lots of catalytic active centers. Moreover, the synergistic effect of Cu2SeS and CoMoCH facilitates the electron transfer. Doping high-valence Mo element into CoCH generates a strong electronic structural interactions between metals. Hence, the CoMoCH–Cu2SeS/NF composite catalyst demonstrates an outstanding OER/HER performance in different alkaline solutions, with a low overpotential and good continuous electrolysis durability. The electrode pair assembled by such a composite catalyst delivers a current density of 100 mA cm−2 at 1.72 V in alkaline simulated seawater. In natural seawater, CoMoCH/NF has a lower electrochemical corrosion rate of 0.85 mm/a than Cu2SeS/NF (9.97 mm/a) and CoCH/NF (5.72 mm/a). The carbonate anions in the CoCH intercalation structure and the doping of Mo element with strong corrosion resistance enhanced the chlorine corrosion resistance of CoMoCH–Cu2SeS/NF in natural seawater and protected the Cu2SeS active components. This research may guide the design and development of high-activity and corrosion-resistant composite electrocatalysts with novel architectures for hydrogen production by seawater electrolysis.