Preparation of phenol-formaldehyde resin-coupled TiO2 and study of photocatalytic activity during phenol degradation under sunlight

In this study, phenol-formaldehyde resin-coupled TiO2 (PF/TiO2) photocatalysts were synthesized via the sol-gel method using tetrabutyl titanate as a precursor and they were tested to determine their activities during the photocatalytic degradation of phenol. The as-synthesized products were characterized using Fourier transform-infrared spectroscopy, X-ray diffraction, UV-visible diffuse reflectance spectroscopy, and transmission electron microscopy. The results showed that TiO2 was in the anatase phase in the as-synthesized PF/TiO2 product and the crystallite size was smaller than that for TiO2. The coupling of PF increased the light absorption capacity of TiO2. Under irradiation with natural sunlight, TiO2 (500 C-degrees, 2 h) obtained a phenol degradation rate of 28.9% after 7.5 h whereas 4% PF/TiO2 (200 C-degrees, 2h) degraded phenol more efficiently (62.8%) in the same time according to high performance liquid chromatography. The higher photocatalytic activity of 4% PF/TiO2 (200 (degrees) C, 2h) can be attributed to a combination of factors, including graphite carbon material formation, a smaller crystallite size, and stronger optical absorption in the visible region. The graphite carbon material facilitated better electron transport and helped to minimize electron-hole recombination in the photocatalyst, thereby enhancing the degradation efficiency.