Synchronized sulfur resource recovery and hydrogen production via a self-powered system based on multifunctional Co3S4 catalyst

Self-driven recycling of sulfur-containing wastewater and hydrogen production is a novel concept that integrates environmental protection and new energy development. In this study, we designed for the first time a Zn-air battery self-driven coupling system for the hydrogen evolution reaction (HER), sulfur oxidation reaction (SOR) and developed a trifunctional catalyst suitable for this system capable of HER, SOR, and oxygen reduction reaction (ORR). By synthesizing cobalt sulfide (Co3S4) in situ on nickel foam (NF), we obtained Co3S4/NF monolithic catalyst. It only requires 0.312 V and 0.244 V in SOR and HER, respectively, at 100 mA cm−2. Based on this achievement, the SOR||HER coupled electrolysis system was assembled, which achieved 0.69 V at 100 mA cm−2. Furthermore, the Zn-air battery (using Co3S4 as ORR catalyst) could spontaneously drive the SOR||HER system to achieve high-rate hydrogen production. These findings provide promising opportunities for zero-energy consumption H2 production and recycling of sulfur-containing wastewater.