Improved dye removal and simultaneous electricity production in a photocatalytic fuel cell coupling with persulfate activation

• Published in: Electrochimica acta 2018-04, Vol.270, p.330-338
• Main Authors: Li, Na, Tang, Shoufeng, Rao, Yandi, Qi, Jinbang, Wang, Pengkai, Jiang, Yang, Huang, Haiming, Gu, Jianmin, Yuan, Deling
• Format: Article
• Language: English
• Subjects: Chemical reactions; Contaminants; Coupling; Decoloring; Dye removal; Dyes; Electric properties; Electricity; Electricity generation; Electrodes; Fuel cells; Hydrogen peroxide; Hydroxyl radicals; Luminous intensity; Nanotubes; Persulfate activation; Photocatalysis; Photocatalytic fuel cell; Scanning electron microscopy; Solid electrodes; TiO2 nanotube arrays; Titanium dioxide; Ultraviolet radiation; X-ray diffraction
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2018.03.083

A coupling method introducing persulfate (PS) into a photocatalytic fuel cell (PFC) was investigated to improve the decoloration of methyl orange (MO) and simultaneous electricity production. The TiO2 nanotube arrays (TNAs) were fabricated successfully on the titanium sheet as the photoanode, which was confirmed by the characterizations of X-ray diffraction and scanning electron microscopy. Due to the characteristics of inorganic sacrificial agent and strong oxidant for PS, the proposed PFC/PS system could improve the photocatalytic reaction and extend the range of active species reaction from the solid electrodes surface to the total liquid phase through the formation of sulfate radical (SO4−) and hydroxyl radical (HO) for MO removal. Hence, PFC/PS exhibited remarkable cell performance, increasing the MO decomposition by 40.36% and electricity generation by 44.97% relative to the PFC system without adding PS. Besides, the pollutant removal ability of the PFC/PS system was systematically assessed at different operation parameters, such as PS concentration, initial MO concentration, initial pH, and UV light intensity. Furthermore, the underlying mechanism of MO elimination was elucidated by the radicals quenching tests and hydrogen peroxide (H2O2) quantitative determination, and these results confirmed that the formation of reactive species, including SO4−, HO, H2O2 and even photogenerated holes, were responsibility for contaminant abatement in the PFC/PS system. [Display omitted] •A synergy adding persulfate into a photocatalytic fuel cell (PFC/PS) was proposed.•PFC/PS improved methyl orange (MO) removal and electricity production simultaneously.•Enhanced removal of MO was mainly attributed to the formation of ▪ and HO.