Synthesis and photochemical properties of La-doped HCa2Nb3O10

The photocatalysts H1−xLaxCa2−xNb3O10 (x = 0, 0.25, 0.5, 0.75) was synthesized by conventional solid state reaction followed by an ion-exchange reaction. They were characterized by power X-ray diffraction, UV–vis diffusive reflectance and scan electron microscope. The effect of substitution of La3+ for Ca2+ in HCa2Nb3O10 has been studied on the photocatalytic decomposition of water under UV light irradiation with methanol as electron donor and Pt as promoter catalyst. Both the optical property and photocatalytic activity of H1−xLaxCa2−xNb3O10 were varied by the substitution of La3+ for Ca2+. The x value in H1−xLaxCa2−xNb3O10 had an important effect on the photocatalytic activity of the catalyst. When the x = 0.5, the H1−xLaxCa2−xNb3O10/Pt showed a photocatalytic activity of 169 cm3 h−1 g−1 hydrogen evolution rate in 10 vol.% methanol solution under irradiation from a 100 W mercy lamp at 333 K.