In-situ utilization of generated electricity in a photocatalytic fuel cell to enhance pollutant degradation

Abstract How to lower recombination of photogenerated electons and holes for efficient pollutant degradation remains a critical challenge for widespread application of photocatalytic fuel cell (PFC). Herein, a PFC based on in-situ utilization of generated electricity for strengthening pollutant removal efficiency was developed. The system was operated in alternate charging and discharging (ACD) mode using a capacitor-based circuit. With the increase of switch time (T s ) from 1 min to 10 min, the rhodamine B (RhB) decolourization rate decreased from 0.05931 min −1 to 0.03879 min −1 with current densities decreasing from 2.58 ± 0.08 A m −2 to 1.86 ± 0.02 A m −2 , which were 133–223% higher than that obtained in continuous energy harvesting (CEH) mode (0.80 ± 0.02 A m −2 ). However, the average power densities increased from 22.2 ± 1.9 mW m −2 to 110.3 ± 3.7 mW m −2 , which were lower than that in CEH mode (154.0 ± 16.7 mW m −2 ). This improvement of current output at the expense of power output was beneficial to minimize the recombination of photogenerated charge carriers and improve RhB decolourization, suggesting the enhancement effect of ACD mode on pollutant degradation compared with CEH mode. This work demonstrates that the electricity produced by PFC could be reused to improve system performance, which also provided a promising avenue of PFC operation for better pollutants removal.