Impact of illumination configuration on the performance of a dual-photoelectrode photocatalytic fuel cell

Abstract

Photocatalytic fuel cell (PFC) is an emerging sustainable technology for simultaneous wastewater remediation and energy recovery. This study investigates the effect of illumination configuration on dual-photoelectrode PFC performance using a batch-scale photocatalytic fuel cell with a working volume of 300 mL. The system utilizes a ZnO-loaded carbon plate as a photoanode and a graphitic carbon nitride (g-C3N4)-loaded carbon plate as a photocathode, since ZnO is a well-established photocatalyst and g-C3N4 is a sustainable and metal-free electrocatalyst. Using 10 ppm hydroquinone as a model organic pollutant under UVA irradiation, two illumination configurations were evaluated: single-sided and double-sided. The results revealed that the double-sided illumination (0.4103 mW m-2) yielded a minor 4.19% increase in maximum power density compared to single-sided illumination (0.3938 mW m-2), which was determined to be statistically non-significant (p = 0.917). These low power densities reflect that the PFC configuration targets organic pollutant degradation as its primary focus, with electricity generation serving merely as a secondary side product. The double-sided illumination demonstrated enhanced photocatalytic activity, with a removal efficiency of 66.35% and a pseudo-first-order rate constant of 0.1913 h-1, surpassing the single-sided illumination (52.19% and 0.1257 h-1). Simultaneously, for both systems, a progressive change was observed at 222 nm, indicating the accumulation of intermediate oxidation products during the degradation process. These results provided fundamental insights into how geometric illumination configuration affects the degradation efficiency and electricity generation in dual-photoelectrode architectures.