Harnessing Wastewater as a Catalyst Modifier for Sustainable Hydrogen Production

Wastewater is considered a growing environmental and economic liability due to the hazards it poses to biota and the ecosystem and the high costs of its treatment. Owing to the diverse nature of wastewater, it can also be a source of valuable materials. Here, we used wastewater active compounds that are naturally deposited on electrode surfaces as a unique catalyst complex. The high electrocatalysis performance of several active ingredients found within wastewater and their synergic effects have rarely been reported. The demonstrated in-situ self-enrichment of the electrode surface catalyst using active ingredients from wastewater enabled continuous water splitting for over 18 days, achieving a high Faradaic efficiency of approximately 89% and a stability of around 95%. This performance fills a significant gap for commercial wastewater electrocatalysts, even surpassing that of Pt/C and IrO-based catalysts. By using two different water sources, we further demonstrate the versatile nature of the developed process. This study explores a concept that eliminates the dependency on freshwater and desalinated water, enabling it to be used even in water-stressed areas to produce economically viable hydrogen.