Simultaneous pollutant degradation and power generation in visible-light responsive photocatalytic fuel cell with an Ag-TiO2 loaded photoanode

Photocatalytic fuel cell (PFC) has been studied for treating phenolic organic pollutants and converting chemical energy into electricity effectively. The photoanode in the anode chamber degraded pollutants by photocatalytic oxidation, while the released electrons were transported to the cathode chamber via an external circuit to participate in the reduction reaction. These reactions enable the conversion of chemical energy into electrical energy. In this study, we firstly used sol-gel method to prepare Ag-TiO2 as the visible-light responsive catalyst. Then we compared two coating methods to obtain effective and stable photoanode with carbon foam as the support, i.e. sol-gel impregnation method and powder spray coating method. The 4-chlorophenol (4-CP), phenol and tetracycline (TC) were selected as the target pollutants. A dual chamber PFC was constructed to examine the pollutants degradation and power generation. The results showed that the photoanode prepared by powder spray coating method presented higher photoactivity and stability. The uniform and stable loading could be obtained when the loading ratio was 0.62 g/g. The degradation efficiency was maintained around 58% and the detachment of photocatalyst was 27.0% after three repeated cycles. In the PFC, the degradation efficiency of 4-CP, phenol and TC reached 32.6%, 37.9% and 96.4% in 6 h and the filling factors (FF) were 0.17, 0.31 and 0.44, respectively.