Study On Paper-based Air-cleaning Materials With Enhanced Photocatalytic Property

Nano-titanium dioxide (TiO2) has characteristics such as stable photocatalytic performance, cleaning and non-toxic, efficient and complete degradation of organic contaminants. The paper with photocatalytic activity got by compositing nano-titanium dioxide to the surface of the paper, has played the role of air purification. However, the present photocatalytic technology based on semiconductor nano TiO2has several key problems such as low quantum yield and low utilization of solar energy, which restrict it widely used in industry. In this paper, two ways to enhanced photocatalytic properties of TiO2were studied in detail.The first method is to make two different band gap semiconductor compounded, whose complementary nature can promote charge separation, inhibit the compound of electron-hole, broaden wavelength range of light-induced excitation, and enhance its stability and photocatalytic activity. We prepared nano ZnO/TiO2complexes by sol-gel process, whose size, morphology, structure and performance were characterized by the atomic force microscope (AFM), UV-Vis spectrophotometer and IR spectra. The photocatalytic properties of samples were detected by the degradation of Methylene blue in solution and the degradation of formaldehyde in air. The results showed that:when nano-ZnO doped ratio was20%and calcination temperature is500℃, the degradation of methylene blue after6h was81%and the degradation of formaldehyde was66%after6h under natural light irradiation, while that of TiO2was55%and51%respectively. The photocatalytic activity were increased by46%and30%.The second method is to make the conjugate polymer and nano-TiO2compounded. Nano-titanium dioxide and furfural was raw materials and sulfuric acid was a catalyst whose volume ratio of concentrated sulfuric acid and water was1:1. The complexes with different nano-scale titanium dioxide and furfural compound ratio were prepared, Characterized and determinate the photocatalytic properties. The results showed that:When nano TiO2and furfural compound ratio was1:2, the degradation of methylene blue after6h can reach99%and the degradation of formaldehyde was77%after6h under natural light irradiation, while that of TiO2was55%and51%respectively. The photocatalytic activity were increased by78%and53%. The compound of conjugated polymer and nano-TiO2does greatly improve the photocatalytic activity of the nano-TiO2.