Efficient visible light photocatalytic water oxidation on Zn3(OH)2V2O7•2H2O nanoplates: Effects of exposed facet and local crystal structure distortion

Zn-3(OH)(2)V2O7 center dot 2H(2)O samples with high visible-light photocatalytic water oxidation activity were hydrothermally fabricated at different pH conditions. The crystalline phase, morphology and local crystal structure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), corresponding selected area diffraction (SAED) and Raman techniques. According to the SEM results, all the samples exhibited aggregates of irregular nanoplates with the average diameter of 100-200 nm and thickness of similar to 20 nm. Furthermore, some factors, such as pH conditions, influencing the morphologies and local crystal structure of the Zn-3(OH)(2)V2O7 center dot 2H(2)O nanoplates have been systematically investigated. The photocatalytic activities of the Zn-3(OH)(2)V2O7 center dot 2H(2)O were evaluated by photocatalytic water oxidation under visible light irradiation. It was found that Zn-3(OH)(2)V2O7 center dot 2H(2)O prepared at low pH exhibited high photocatalytic water oxidation activity, indicating that different morphologies and the different extent of local crystal structure distortion can effectively influence the water oxidation activity of Zn-3(OH)(2)V2O7 center dot 2H(2)O . Moreover, the relationship between the exposed facets of Zn-3(OH)(2)V2O7 center dot 2H(2)O and the H2O molecule adsorption was investigated by density functional theory (DFT). The results of our study indicated that the extent of connection between polyhedrons on exposed facet of the Zn-3(OH)(2)V2O7 center dot 2H(2)O can significantly affect the sample's H2O molecule adsorption activity. (C) 2015 Elsevier B.V. All rights reserved.