Facet-Dependent Photocatalytic Behaviors of ZnS-Decorated Cu2O Polyhedra Arising from Tunable Interfacial Band Alignment

• DOI: 10.1021/acsami.8b19197
• Publication Date: 2018-12-28T15:59:49Z
• Authors: Gollapally Naresh; Pei-Lun Hsieh; Vandana Meena; Shih-Kuang Lee; Yi-Hsuan Chiu; Mahesh Madasu; An-Ting Lee; Hsin-Yi Tsai; Ting-Hsuan Lai; Yung-Jung Hsu; Yu-Chieh Lo; Michael H. Huang
• Keywords: Facet (psychology); Polyhedron

ZnS particles were grown over Cu2O cubes, octahedra, and rhombic dodecahedra for examination of their facet-dependent photocatalytic behaviors. After growth, cubes stay photocatalytically inactive. ZnS-decorated octahedra show enhanced activity, resulting from better charge carrier separation upon photoexcitation. Surprisingly, give greatly suppressed activity after deposition. Electron paramagnetic resonance spectra agree with these experimental observations. Time-resolved photoluminescence profiles provide charge-transfer insights. The decrease in the is attributed to an unfavorable band alignment caused by significant bending within Cu2O(110)/ZnS(200) plane interface. A modified Cu2O–ZnS diagram presented. Density functional theory calculations generating plane-specific energy diagrams match well results, showing that transfer across interface would not happen. This example further illustrates actual photocatalysis outcome semiconductor heterojunctions cannot be assumed because interfacial strongly facet-dependent.