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

Facet (psychology) Polyhedron
DOI: 10.1021/acsami.8b19197 Publication Date: 2018-12-28T15:59:49Z
ABSTRACT
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.
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