Exploring CuO/Nano Graphitic Carbon Nitride Composites as Photocathode in Photocatalytic Fuel Cells

Photocatalytic fuel cells (PFCs) offer a sustainable approach to energy conversion from organic pollutants, but their efficiency is often hindered by the cathode, which has a slow oxygen reduction reaction (ORR) and limits the transportation of electrons to the cathode from the photoanode. In this study, CuO/nano g-C₃N₄ composites with different CuO ratios were synthesized and loaded onto carbon plates as cathodes to enhance ORR activity for Reactive Red 120 (RR120) degradation and generation of electricity in the PFC system. The synthesized nano g-C3N4 and its composites were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), nitrogen adsorption–desorption analysis and field emission scanning electron microscopy (FE-SEM). The results disclosed that the application of CuO/nano g-C3N4 as the cathode under dual photoelectrode configuration promoted charge separation and facilitated electron transfer and achieved optimal PFC performance, with a 98.46% removal efficiency and maximum power density (Pmax), 1.351 mW/m2, which was 167.15% higher than the pristine nano g-C3N4. These discoveries highlighted the potential of CuO-modified nano g-C₃N₄ composites in improving ORR efficiency and generating electricity.