The significant role of few sulfite replenishment in boosting electricity generation and organic wastewater degradation in photocatalytic fuel cell

The performance of electricity generation and organic wastewater degradation are two important indicators to evaluate photocatalytic fuel cell (PFC). However, data related to the impact of sulfite, especially few sulfite replenishment on PFC properties are scare. In this paper, a porous sheet-like BiVO4 photoanode was first prepared and then a self-biasing BiVO4-Au/BJS (BJS: buried junction silicon) PFC is constructed. The results show that the BiVO4 film exhibited an optimal water splitting photocurrent density of 1.15 mA cm(-2) at 1.23 V vs. RHE. The PFC system can be operated without any external bias and showed high converting performance of organic into electricity. With the total addition of only 2 mM sulfite, a short-circuit current density of 0.61 mA cm(-2), which is obviously higher than the BiVO4-Au/BJS system without sulfite, was obtained with maximum power output of 6.5 x 10(-4) W cm(-2) in 10 mg L-1 methyl orange. Furthermore, a removal ratio of 93.78% after 2 h was achieved with stable current output in the degradation process, compared with the removal ratio of 40.63% without sulfite. More importantly, TOC removal ratio also increased sharply from 30.2% to 85.4%. EPR test demonstrates that radicals including (OH)-O-center dot and (SO4-)-S-center dot cogenerated in system.

Automated summary

This study investigated the impact of sulfite on the performance of photocatalytic fuel cells, revealing that sulfite can enhance current density and power output, while also significantly improving the degradation of organic wastewater.