Photocatalytic Degradation of Phenol with Bacteriorhodopsin Sensitized TiO₂ Nanoparticles

Bacteriorhodopsin (BR) is a light driven proton pump firstly found in the membrane of halophilic archaea. BR absorbs wide range of visible light with high quantum efficiency. To elucidate the sensitizing effect of BR, we tested the photocatalytic degradation of phenol with BR-sensitized TiO2 nanoparticles and compared with that of Alizarin red (AR). When the concentration of BR was 13.1 mg/L (4.9×10-7 mol/L), 23.8% of phenol was degradated after 2 hours of light irradiation. The degradation percentage was 3.5 times higher than that with TiO2 nanoparticles alone and similar to that sensitized by AR (20.1%). The possibilities and approaches to increase the sensitizing performance of BR were discussed.