Methanol-assisted energy-saving green hydrogen production using electrodeposited 3D-metallic tin as an electrocatalyst

Abstract

Sustainable hydrogen production via developing an efficient water-splitting device plays a major role in achieving carbon neutrality. However, the efficiency of traditional water electrolysis is severely hindered by the sluggish kinetics of the oxygen evolution reaction (OER). To overcome this limitation and boost hydrogen production, the OER can be replaced by the thermodynamically feasible methanol oxidation reaction (MOR). Herein, we electrochemically deposited 3D metallic tin on nickel foam (3D Sn/NF) and explored the bi-functional electrocatalytic properties of tin when used in a hybrid water electrolyzer. The 3D Sn/NF grown with 15 min of Sn deposition (3D Sn/NF-15) exhibited excellent HER, OER, and MOR performances with low overpotentials of 130, 300, and 160 mV at a current density of 10 mA cm⁻². Furthermore, we designed a MOR-mediated water electrolyzer using 3D Sn/NF-15 as a bifunctional catalyst, which required a cell voltage of only 1.54 V to achieve a current density of 10 mA cm⁻², which is 70 mV lower than that required by a conventional water electrolyzer. Furthermore, a real-time hybrid water electrolysis system built with an H-type electrolytic cell showed exceptional hydrogen production, with a faradaic efficiency of 98%. Overall, this work paves the way for the facile preparation of monometallic catalysts for next-generation electrochemical energy conversion devices.