Structural, morphological and photocatalytic characterisations of Ag-coated anatase TiO_2 fabricated by the sol-gel dip-coating method

摘要

This study reports on the synthesis, characterisation and environmental applications of immobilised Titanium dioxide (TiO_2) as photocatalyst. Nanostructured thin films have been prepared on glass substrates using a layer-by-layer dip-coating method. The crystalline phase and surface morphology of the thin films were investigated by X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM), respectively. The XRD results show that the TiO_2 thin films crystallise in anatase phase and we have found that the thin films consist of titanium dioxide nanocrystals. SEM shows that the nanoparticles are sintered together to form a compact structure and TiO_2 particles coated with silver nanoclusters were observed. Ag-coated TiO_2 films demonstrated photocatalysis performance when irradiated, and the Ag carrier further showed an electron-scavenging ability to mitigate electron-hole pair recombination, which can improve the photocatalytic efficiency. With the oxidisation and electron-scavenging ability of Ag and the photocatalysis ability of TiO_2, Ag-coated TiO_2 can decolour methyl orange (MO) more than bare TiO_2. It is a new approach to form Ag-coated TiO_2 nanoparticles with a simple system and nontoxic materials. The high photocatalytic effect of Ag-coated TiO_2 nanoparticles on pollutant (MO) suggests that it may have a promising future for water and wastewater treatments.