Solar‐Driven Photoelectrochemical Technologies for Wastewater Treatment and Green Hydrogen Production

Abstract

Over the past few decades, there has been an urgent need to develop innovative water treatment technologies for eliminating pathogens and persistent micropollutants (e.g., pharmaceuticals and personal care products) that are commonly found in different waste streams with a wide range of concentrations (i.e., micrograms to nanograms per liter). More importantly, the scarce availability of valuable resources is the main reason for shifting our societal attention away from traditional waste management and disposal methods toward the recovery of resources from wastewater. A potential approach for water and wastewater treatment that generates net energy is solar-driven photoelectrochemical cells (PECs). Photoelectrochemical technologies open up opportunities to efficiently degrade recalcitrant wastewater and generate renewable energy compared to traditional advanced oxidation processes owing to their outstanding treatment efficiency and renewable energy production, mainly due to the synergistic impact of photochemical and electrolysis reactions in PEC. This book chapter provided a critical assessment of the current advances in photoelectrochemical technologies, including fundamental reaction mechanisms of different photoelectrochemical methods. The synergistic effects of various combined photochemical, electrochemical, and photoelectrochemical processes were also discussed. The performance capability of modified photoanode and cathode materials used in photoelectrochemical reactors was described. Finally, the photoelectrochemical treatment of real wastewater for hydrogen production was reviewed.