La sub(2)Ti sub(2)O sub(7): An efficient and stable photocatalyst for the photoreduction of Cr(VI) ions in water

In the present work, the photocatalytic activity of La sub(2)Ti sub(2)O sub(7) for the photoreduction of Cr(VI) ions in water was investigated. The results indicated that La sub(2)Ti sub(2)O sub(7) is an efficient photocatalyst with 98% of reduction efficiency of Cr(VI) ions after 3h ultraviolet (UV) irradiation. Meanwhile, the stability of La sub(2)Ti sub(2)O sub(7) in the photocatalysis was investigated by repeatedly performing Cr(VI) photoreducing experiments. It can be found that the photocatalytic activity of La sub(2)Ti sub(2)O sub(7) remained almost unchanged after nine successive cycles, and the reduction ratio of Cr(VI) ions was still up to 50% in the twentieth cycle. Furthermore, for practical purposes, the photocatalytic reduction of Cr(VI) ions was studied as functions of the solution pH, initial Cr(VI) concentration and additional salts.