First principle investigation of the exposed surfaces and morphology of beta-ZnMoO4

Abstract: Crystal shape is a critical determinant of the physical and chemical properties of crystalline materials; hence, it is the challenge of controlling the crystal morphology in a wide range of scientific and technological applications. The morphology is related to the geometry of their exposed surfaces, which can be described by their surface energies. The surface properties of beta-ZnMoO4 have not yet been well explored, either experimentally or theoretically. Thus, the first-principle calculation at the density functional theory level was carried out for different low-index surfaces of beta-ZnMoO4, specifically (001), (010), (110), (011), (101), and (111), and the surface energy values (E-surf) were reported. The surface stability was found to be controlled by the undercoordinated [MoOn … yV(O)(x)] and [ZnOn … yV(O)(x)] (n = 4 and 5; y = 1 and 2) clusters, i.e., their local coordination of Mo and Zn cations at the exposed surfaces, respectively, with the (111) surface being the most stable. A complete map of investigated beta-ZnMoO4 morphologies was obtained using the Wulff construction and changing the values of the calculated energy surfaces. The final geometries from this map were compared with field emission-scanning electron microscopy images showing excellent agreement, prevising rectangular and hexagonal plates. Our findings will promote the use of facet engineering and might provide strategies to produce beta-ZnMoO4-based materials for achieving morphology-dependent technological applications. Published under license by AIP Publishing.

Author(s): Ribeiro, RAP ; Oliveira, MC ; de Sousa, AG; Bomio, MRD ; Motta, FV; Gracia, L ; de Lazaro, SR ; Longo, E ; Andres, J