Hydrogen production from photoelectrochemical wastewater treatment: advancing toward sustainability

Abstract

Incorporating green hydrogen production into photoelectrochemical (PEC) wastewater treatment has been demonstrated as a promising approach to enhance the sustainability of wastewater treatment. Such a bifunctional PEC system eliminates the dependence of water splitting on pure water consumption and enables wastewater valorization. This critical review initially delves into the advances in developing photoelectrodes for bifunctional PEC systems and summarizes the involved modification approaches. Subsequently, the review provides a comprehensive analysis of strategies for optimizing the operation of bifunctional PEC systems and impacts from the wastewater matrices. Furthermore, the challenges presented in the industrialization of this technology are also pointed out. As such, further investigations are encouraged into the scale-up of the PEC reactor, the prolongation of photoelectrode lifespan, the development of downstream hydrogen storage techniques, cost-effectiveness assessment, and the strategy against external variations, thus advancing the bifunctional PEC technique toward industrialization.