A novel scheelite-like structure of BaBi2Mo4O16: Photocatalysis and investigation of the solid solution, BaBi2Mo4−xWxO16 (0.25 ≤ x ≤ 1)

A barium bismuth molybdate, BaBi2Mo4O16, was synthesized for the first time. The compound was made by the solid-state technique and studied for photocatalytic degradation of water pollutants. The compound crystallizes in the monoclinic C2/c system with a = 5.317 (1) Å, b = 12.875 (2) Å, c = 19.390 (3) Å, β = 101.512 (4)°, V = 1327.1 (4) Å3 and Z = 4. The crystal structure along the a-axis consists of layers of [Bi2O2] units and BaO10 polyhedra both surrounded by isolated MoO4 tetrahedra representing a scheelite-like structure. Photocatalytic degradation of phenols and substituted phenols, acids and dyes were studied using BaBi2Mo4O16 as catalyst. The catalyst shows selectivity towards chlorine containing aromatics. Substitution of tungsten for molybdenum resulted in retention of structure within the limits 0.25 ≤ x ≤ 1 of the solid solution, BaBi2Mo4−xWxO16. The phases, x = 0.25, 0.50, 0.75 and 1.0, in the solid solution were also used to study the photocatalytic degradation of water pollutants like phenol, substituted phenols and dyes. The photocatalytic activity increases slightly with an increase in substitution of tungsten in the solid solution domain.