Phase- and Morphology-Controlled Synthesis of Zinc Molybdate for Excellent Photocatalytic Properties

This paper reports the phase- and morphology-controlled synthesis of zinc molybdate using a hydrothermal route. With increasing monomer concentrations, the morphology and phase of the products transfer from ZnMoO4 plates (monoclinic phase) to ZnMoO4<bold></bold>0.8H(2)O rod bundles (triclinic phase). The morphology and phase conversions of the products are monitored with the help of SEM, TEM, and XRD. A possible mechanism for the formation of the products is proposed. The optical properties of zinc molybdate are characterized. The band-gap values of zinc molybdate are in the range of approximately 2.71-3.05 eV. With the use of the photocatalytic degradation of RhB as a probe reaction, the photocatalytic performance of - and -zinc molybdate is investigated. The degradation efficiency of RhB over calcined -ZnMoO4<bold></bold>0.8H(2)O is up to 89%. The calcined -ZnMoO4 plate exhibits the highest activity for the degradation of RhB, up to 98%. The radical-trapping experiments evidence (<bold>)</bold>O-2(-) and H+ as being the main reactive species. Some possible factors influencing the photocatalytic activity of the products are discussed.