Dramatic enhancement of visible light photocatalysis due to strong interaction between TiO2 and end-group functionalized P3HT

Abstract

Conjugated polymer/TiO2 photocatalysts hold great promise for solar chemical conversion processes by combining the advantages from both the conjugated polymer and the inorganic semiconductor, overcoming the serious drawbacks of fast charge recombination and the limited visible light absorption of inorganic semiconductor through interfacial electron transfer. To address the crucial way to promote the visible light photocatalytic activity of conjugated polymers/TiO2 photocatalysts, P3HT/TiO2 composites with strong interfacial interaction between P3HT and TiO2, which was demonstrated by the results of X-ray photoelectron spectroscopy and dissolution tests, were prepared by binding cyanoacrylic acid end-groups functionalized P3HT to the surface of TiO2. The pseudo-first-order kinetic constants of photocatalytic degradation of model pollutant methyl orange (MO) under visible light with P3HT/TiO2 composites of monofunctionalized and difunctionalized polymers were 7.06 and 20.18 times as great as that of unfunctionalized polymer, respectively, indicating a remarkably enhanced visible light photocatalytic activities by an order of magnitude with the incorporation of cyanoarrylic acid end-groups. In consideration of their similar morphology, specific surface area, ability of harvesting visible light and adsorption capacities toward MO independent of end-group functionalization, the dramatically enhanced photocatalytic activity arises from the facilitated electron injection and separation of photogenerated carriers owing to strong interfacial interaction between TiO2 and end-group functionalized P3HT, which was proved to be crucial for photocatalytic capability of conjugated polymer/TiO2 photocatalysts, providing a new effective direction for the improvement of their visible light photocatalytic activity.