Degradation of Rhodamine B using a Visible-light driven Photocatalytic Fuel Cell

A visible-light driven Photocatalytic Fuel Cell (PFC) system comprising WO3/TiO2 and CuO/TiO2 nanotube array materials as photoanode and photocathode, was established with a dual objective of degrading an organic water pollutant and generating electric power as well. Under illumination, the Fermi level of WO3/TiO2 nanotube arrays photoanode was higher than that of CuO/TiO2 nanotube arrays photocathode. Arising an interior bias (0.18 V) induced the transfer of electrons from the photoanode across the external circuit to the photocathode and combination with the holes produced therein with electric power generation. In this manner, the separation of electron/hole pair was achieved in the photoelectrodes by releasing the holes of WO3/TiO2 nanotube arrays photoanode and electrons of CuO/TiO2 nanotube arrays photocathode. Using this PFC based system, the degradation of an organic water pollutant, Rhodamine B, was successfully accomplished with determining its decolorization and the variation in total organic carbon (TOC) content. The decolorization and TOC removal were obtained to the extent of 100% and 57%, respectively at 4 h reaction time. The stability of the photoelectrodes for scaling up applications could also be confirmed by the repeated several experimental runs using the electrodes. The proposed photoelectrocatalytic system provides a self-sustained and energy-saving methodology for wastewater treatment with a parallel energy production.