Solar-driven hybrid photocatalytic fuel cells for concurrent wastewater treatment and energy generation

Photocatalytic Fuel Cells (PFCs) present a promising approach for wastewater treatment and sustainable energy generation. This study developes single-cell PFCs and hybrid PFC systems by integrating PFCs with electrocatalytic (ECR) or photoelectrocatalytic reactors (PECR) to treat wastewater and energy generation as concomitant. Solar-driven photoanodes, specifically Fe or Cu-doped g-C₃N₄ (CN), are utilized alongside an air-breathable cathode and a supercapacitor. Characterization study confirms their successful analysis. A supercapacitor provides that PFCs are worked under dark conditions. In single-cell PFC, optimal power density of 0.1794 mW/m² is achieved at pH 12 with a Cu/CN catalyst loading of 2 mg/cm² and 0.25 mM KOH. Hybrid systems exhibits higher power densities, with 0.8704 mW/m² for PFC-ECR and 0.5614 mW/m² for PFC-PECR. The catalyst loading and its interaction with pH are critical in PFC-ECR, while pH alone significantly impacts power density in PFC-PECR. A kinetic study in the PFC-ECR system, conducts at 25, 35, and 45 °C using a Cu/CN photoanode, indicates that the reaction follows a first-order kinetic model.