Photochemical reduction of nitrate to ammonia using layered hydrous titanate/cadmium sulphide nanocomposites

The photocatalytic activity of H2Ti4O9/CdS nanocomposites incorporating CdS particles, less than 0·8 nm thick, in the interlayer of H2Ti4O9 was evaluated for the reduction of NO3− with and without methanol. NO3− was photochemically reduced by bandgap illumination in the presence of H2Ti4O9/CdS nanocomposites with and without methanol although unsupported CdS showed no noticeable photocatalytic activity for NO3− reduction. The oxidation of CdS in H2Ti4O9/CdS to SO42- was accompanied by NO3− reduction without methanol, whereas addition of methanol was useful to promote the NO3− reduction and depress the oxidation of CdS. The catalytic activity of H2Ti4O9/CdS greatly increased with doping Pt particles in the interlayer.