A STUDY OF TITANIUM DIOXIDE AND SODIUM TANTALATE FOR PHOTOCATALYTIC WATER SPLITTING

Abstract

Photocatalytic water splitting using sunlight remains as one of the most convenient and accessible methods to extract renewable solar energy. In this study, titanium dioxide-copper sulfide (TiO2/CuxS) nanocomposites and sodium tantalate (NaTaO3) films are separately studied as potential water splitting photocatalysts. Water-soluble Cu2S was first prepared from decomposing a single precursor, and TiO2/CuxS nanocomposites were prepared by introducing TiO2 during the decomposition process. It was also found that a physical mixture of TiO2 and Cu2S displayed comparable activity to that of the nanocomposite. Further investigations suggested that the Cu2S had decomposed during the water splitting to form metallic Cu on the TiO2 surface. NaTaO3 nanocubes on substrate was prepared by soaking tantalum metal in sodium hydroxide under hydrothermal conditions. The effect of temperature and of base strength and concentration on the formation of the product was studied, and a mechanism of formation of NaTaO3 was proposed. The photocatalytic water splitting activity of NaTaO3 was studied and found to be lower than literature values due to loss of surface area from attachment to the substrate.