The role of counter-ions in crystal morphology, surface structure and photocatalytic activity of ZnO crystals grown onto a substrate

Abstract

In this contribution, we present an experimental and theoretical investigation of the role of counter-ions in the crystal morphology, surface structure, and photocatalytic activity of hierarchical ZnO nanostructures. The effect of zinc precursor (nitrate, acetate and, sulfate) along the synthesis of ZnO nanostructures grown directly onto a substrate by means of a simple hydrothermal method was analyzed in detail. Scanning electron microscopy images showed a preferential growth of ZnO nanostructures along the caxis, with a slight reduction in the orientation depending on the choice of the Zn source. 2 Theoretical calculations based on Wulff theory allowed us a better understanding of the morphological changes and to directly relate the photocatalytic performance at the different exposed surfaces of the as-observed crystal shapes. Our results showed that photocatalytic activities in the discoloration of organic dyes became superior for hierarchical ZnO nanostructures obtained from zinc nitrate. This finding was explained by X-ray photoelectron and photoluminescence spectroscopies, which revealed that the presence of surface defects, as well as the attached counter-ions and the abundance of carboxylate groups and organic residuals on ZnO surfaces are determinant for enhanced photocatalytic performance.

Bridging experiment and theory: Morphology, optical, electronic, and magnetic properties of MnWO4

“…This procedure has been performed to obtain the complete set of morphologies of different materials based on the Wulff construction and the values of E surf and to investigate the magnetic and multiferroic properties of different materials [19,37,[41][42][43][44][45][46][47][48], in addition to pathways connecting the different morphologies. The energy (E pol ) and band gap energy (E poly gap ) of the polyhedron were calculated by assuming the contributions from each surface to the morphology (C (hkl) i…”

van der Waals g-C3N4/BiLuWO6 Heterojunctions from Theoretical Predictions to Photocatalytic Applications

“…Reducing water pollution and producing clean energy can effectively improve the living environment of humans. , Green and friendly photocatalysis technology has been applied to the degradation of various contaminants in water and H 2 generation from water decomposition . Band gap, CB, and VB edge positions of semiconductor determine its light absorption capacity and reaction activity. , Generally, the photocatalytic performance of intrinsic materials is unsatisfactory for large-scale applications. − …”