Copper doping and organic sensitization enhance photocatalytic activity of titanium dioxide: Efficient degradation of phenol and tetrabromobisphenol A.

A novel photocatalyst (Cu-TiO2@HQ) had been synthesized by combining Cu-doped TiO2 nanoparticles with 8-Hydroxyquinoline (HQ) via hydrothermal method. The photocatalytic activities of Cu-TiO2@HQ were investigated by using phenol and tetrabromobisphenol A (TBBPA) as target pollutants, respectively. The results indicated that the degradation efficiencies of phenol and TBBPA by Cu-TiO2@HQ were 99.2% (in 30 min) and 99.4% (in 10 min) under visible light irradiation. Both of them were much better than that of pure TiO2 (8.63% in 30 min) and Cu-TiO2 (14.74% in 30 min). When phenol or TBBPA were degraded together with the reduction of Cr (VI), the reaction rate of each pollutant was significantly increased, and the cyclic stability of photocatalyst Cu-TiO2@HQ was greatly improved. Based on the spectroscopic and photoelectric characteristic analysis we found that in the mixture of phenol-Cr (VI) or TBBPA-Cr (VI) both photo-generated electrons and holes can be consumed simultaneously, thus preventing their recombination. The possible degradation products of phenol and TBBPA including its degradation path way were also analyzed by high resolution liquid chromatography-mass spectrometry-mass spectrometry.