Synthesis of TiO_2-SiO_2 Powder Using Sol-Gel Method for Photocatalyst Applications

摘要

Nanosized powder binary oxide of TiO_2-SiO_2 photocatalyst was successfully produced via sol-gel method. Its composition was varied at TiO_2(90%)- SiO2(10%) (powder A) and TiO_2 (70%}-SiO_2(30%) (powder B). Its physico-chemical properties were characterized using XRD, FT-IR, TG-DTA, FESEM, and BET surface area analyzer. TEOS and acetylacetonate-chelated titanium diisopropoxide (PTP) has been selected as the starting materials. Methanol, hydrochloric acid and distilled water was used to hydrolyze the TEOS partially. The mol ratio of H_2O: TEOS and HC1: TEOS was fixed at 2 and 0.1, respectively. PTP was added to the partially hydrolyzed TEOS to form polytitanosiloxane precursor solution (PTS) through polycondensation process. The powder was obtained through dissolution process of PTS solution with acetone and followed by pouring hexane. XRD analysis showed that purely anatase crystal structure was obtained after calcination at 500°C. Nanosizer analysis snowed that the powder B (137.4nm) has smaller size compared to powder A (156.8nm). It seems that the addition SiO_2 has suppressive effect on the grain growth of TiO_2 crystal and gives a small particle size. Acetaldehyde was chosen as a pollutant to be used in evaluating the photocatalytic performance.