Advanced oxidation treatment of amaranth dye synchronized with electricity generation using carbon-based cathodes in a sustainable photocatalytic fuel cell integrated electro-fenton system

Abstract Cathodes are key components in the photocatalytic fuel cell (PFC) integrated electro-Fenton (EF) system (PFC-EF system) as they play significant role in connecting PFC and EF for the external transfer of electrons. In this study, three ubiquitous carbon-based materials (carbon felt (CF), carbon plate (CP) and carbon cloth (CC) were used as cathodes in the PFC-EF system to explore the efficiency of these materials in Amaranth degradation and electricity generation synchronously. Interestingly, the dye decolourisation efficiency in both PFC and EF decreased in the sequence of CF > CP > CC. The highest concentration of hydrogen peroxide (0.289 mM) was electro-generated on CF in the EF process of the integrated system. CF achieved the highest voltage output of 202.6 mV and maximum power density (Pmax) of 3.560 μW cm-2, which was 2.5-fold and 12.1-fold higher than that of CP and CC, respectively. The photolysis reaction of UV contributed to the higher oxidizing power of PFC integrated photo-electro-Fenton (PEF) system in dye degradation compared with that of the existing PFC-EF system. Enhanced decolourisation efficiencies of 98.97% and 96.46% were respectively achieved in PFC and PEF with Pmax of 4.017 μW cm-2.