Hybrid photocatalytic fuel cells: recent advances and future prospects for sustainable pollutant degradation and power generation

Environmental pollution and the energy crisis have attracted worldwide attention. The uncontrolled release of large quantities of organic/inorganic pollutants into water bodies severely harms the environment. Nevertheless, these organic pollutants represent valuable sources of carbon and energy that could be sustainably harnessed instead of being wasted. Photocatalysis process is an exciting technology with great potential for solving complex problems, including environmental pollution and sustainable power generation. Recent technological advancements have facilitated the integration of photocatalysis (PC) and fuel-cell (FC) technologies, leading to the development of photocatalytic fuel cells (PFCs) capable of simultaneously treating wastewater and generating electricity. To enhance the performance of PFC systems, researchers investigated various strategies, including developing highly efficient photoelectrodes with visible-light responsiveness, designing innovative hybrid cells combine traditional treatment/technique systems with PFCs, employing dual photo-electrode configurations, and optimizing operational parameters. This review specifically aims to provide a comprehensive overview of the recent advancements in the design of various photocatalytic fuel cell (PFC) systems developed in recent years. It also highlights the materials utilized in constructing photoelectrodes, emphasizing their roles in enhancing system performance. Furthermore, it is found that some new designs combine the existing conventional PFCs with other designs/systems such as airlift reactors, electro-fenton, photovoltaic cells, and rotating discs electrodes in innovative systems to take advantage of the benefits that these systems such as good mixing and increased mass transfer rates, and thus achieving high performance in terms of power generation and wastewater treatment.