Effect of Ni Substitution on the Structure and Photocatalytic Activity of InTaO₄ Under Visible Light Irradiation

The effect of Ni substitution on the structure and photocatalytic H₂ and O₂ evolutions of InTaO₄ under visible light irradiation (λ > 420 nm) from aqueous CH₃OH/H₂O and AgNO₃/H₂O solutions were investigated. The photocatalysts were prepared by the solid-state reaction method and characterized by powder x-ray diffraction and Rietveld structure refinement. These photocatalysts crystallize in the same wolframite structure, but lattice parameters decrease with increase of x in In_1−xNi_xTaO₄ (0 ≤x ≤ 0.2). The photocatalytic activity changed with the variation of x in In_1−xNi_xTaO₄and the photocatalyst at x = 0.1 showed the highest activity, which increased 8 times compared with nonsubstituted photocatalyst.