Comparative Study of Photocatalytic Fuel Cell for Degradation of Methylene Blue under Sunlight and Ultra-Violet Light Irradiation

Photocatalytic fuel cell is considered as a sustainable wastewater treatment system which could degrade organic pollutants and generate electricity simultaneously. In this study, a single-chambered photocatalytic fuel cell based on immobilized ZnO/Zn photoanode was evaluated under sunlight and UV light irradiation, respectively. Methylene blue was used as the dye pollutant in the photocatalytic fuel cell. The fabricated ZnO/Zn photoanode was characterized using scanning electron microscopy and X-ray diffraction. Significant difference in degradation efficiency of methylene blue was observed under UV and sunlight irradiation, respectively. Results showed that the decolorization efficiency and electricity generation of methylene blue in PFC and photolysis were higher under sunlight irradiation compared to those of the UV light irradiation. The decolorization trend of methylene blue was unstable under photolysis using UV light irradiation. Under sunlight irradiation, about 85% of methylene blue was decolorized by PFC, but only 35% of decolorization was observed under UV light irradiation. The maximum power density of the PFC under sunlight irradiation (0.0032 mW/cm2) was almost two times of that under the UV light irradiation (0.0017 mW/cm2).