Poly(4-vinylphenol) as a new stable and metal-free sensitizer of titania for visible light photocatalysis through ligand-to-metal charge transfer process
By Zhang, Guan; Kim, Chuhyung; Choi, Wonyong
Published in Catalysis Today
2017
Abstract
Abstract In this study, poly (4-vinylphenol) (denoted as PVP) was firstly used as a stable and low-cost sensitizer of titania for visible light photocatalysis. The {PVP} thin-layer was readily grafted on TiO2 (PVP/TiO2) through surface complexation between the multiple hydroxyl groups of {PVP} and the surface titanol groups (Ti-OH), via simple dispersion of {PVP} and TiO2 powders in organic solvent. We have demonstrated that the {PVP} layer sensitizes TiO2 under visible light through the ligand-to-metal charge transfer (LMCT) mechanism. The PVP/TiO2 (with platinum as co-catalyst) composite exhibited a visible light activity of {H2} production in the presence of suitable electron donors, whereas phenol-complexed TiO2 (compared as a control) did not generate {H2} in the identical condition. Furthermore, PVP/TiO2 exhibited efficient photocatalytic degradation of organic pollutant (4-cholorophenol) under visible light irradiation. In addition, the photoelectrochemical measurements for PVP/TiO2-coated electrodes (PVP/TiO2/FTO) supported the visible light-induced {LMCT} process on PVP/TiO2, which involves the direct electron transfer from the highest occupied molecular orbital (HOMO) of {PVP} to the conduction band of TiO2 as the origin of the visible light photocatalytic activity.