Synthesis of TiO₂/Au Nanocomposites via Sol-Gel Process for Photooxidation of Methanol

Abstract

Well-ordered TiO₂/Au nanocomposites were prepared using sol-gel process in presence of poly(ethylene oxide)₁₀₆-poly(propylene oxide)₇₀-poly(ethylene oxide)₁₀₆ triblock copolymer (Pluronic F127) as the structuredirecting agents. The content of Au into TiO₂ network was amounted to be 0.3, 0.5, 1 and 2 wt%. The produced TiO₂/Au gels were calcined at 500 °C for 4 hours under atmospheric conditions. The findings indicated that TEM images of 2 wt%Au/TiO₂ nanocomposites correspondeds anatase TiO₂ nanoparticles, which mainly consisted of nanoscale cubes and rhombohedra. These nanoparticles are homogenously distribution and have average sizes of TiO₂ and Au 12 ± 2 and 20 ± 5 nm respectively. TiO₂/Au nanocomposites were investigated for their photooxidation efficiencies for methanol to produce formaldehyde at room temperature. The results indicated that, the TiO₂/Au nanocomposites show good performance in methanol photooxidation due to their highly ordered crystalline, one crystal phase, small particle size and strong adsorptive capacity. Additionally, the results of this study demonstrate that 1 wt%Au/TiO₂ is more photoactive than pure TiO₂ and P25 degussa. The photonic efficiencies of the TiO₂/Au nanocomposites at varies Au content was determined. In general, a large surface area, and highly TiO₂ crystalline anatase obtained contributes high adsorptive capacity and hence resulting in high photocatalytic activity.