Fabrication of Ag@AgCl/ZnO submicron wire film catalyst on glass substrate with excellent visible light photocatalytic activity and reusability

Conventional ZnO powder catalysts possess excellent stability and photocatalytic activity, but have great difficulties for separation and regeneration after the reaction and require ultraviolet irradiation (less than 5% of solar energy), thus restricting practical applications. In this paper, unique short submicron wire-like ZnO films were successfully prepared on silicate glass substrates by calcination of spin-coated zinc acetate solution in the presence of ethanolamine (EA). A typical synthesis yields ZnO submicron wires with ca. 50-120 nm in diameter, 15-30 mu m in length and 0.5-1.5 mu m in height. Ag@AgCl particles were deposited on short ZnO submicron wire films by a simple impregnating-precipitation-photoreduction method. The as-prepared Ag@AgCl/ZnO film exhibited efficient photocatalytic performance under visible light irradiation and excellent self-cleaning capability under solar light. This film photocatalysts were easy to separate from the reaction, and the tests showed that the films were reusable for four times without significantly loosing efficiency. Additionally, gas chromatography- mass spectroscopy (GC-MS) was applied to investigate the degraded chemical species resulted from the photo-catalytic degradation of methylene blue (MB) and methyl orange (MO) dyes under Ag@AgCl/ZnO. A possible photocatalytic mechanism was proposed based on the photoelectrochemical measurements and radical trapping experiments.