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 ZnMoO 4 plates (monoclinic phase) to ZnMoO 4 · 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 α‐ and β‐zinc molybdate is investigated. The degradation efficiency of RhB over calcined α‐ZnMoO 4 · 0.8H 2 O is up to 89 %. The calcined β‐ZnMoO 4 plate exhibits the highest activity for the degradation of RhB, up to 98 %. The radical‐trapping experiments evidence · O 2 – and H + as being the main reactive species. Some possible factors influencing the photocatalytic activity of the products are discussed.