Structural, morphological and photocatalytic characterisations of Ag-coated anatase TiO2 fabricated by the sol–gel dip-coating method

Abstract

This study reports on the synthesis, characterisation and environmental applications of immobilised Titanium dioxide (TiO2) 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 TiO2 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 TiO2 particles coated with silver nanoclusters were observed. Ag-coated TiO2 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 TiO2, Ag-coated TiO2 can decolour methyl orange (MO) more than bare TiO2. It is a new approach to form Ag-coated TiO2 nanoparticles with a simple system and non-toxic materials. The high photocatalytic effect of Ag-coated TiO2 nanoparticles on pollutant (MO) suggests that it may have a promising future for water and wastewater treatments.