title: Synthesis of Cu2O Octadecahedron/TiO2 Quantum Dot Heterojunctions with High Visible Light Photocatalytic Activity and High Stability.
abstract: Since p-n heterojunction photocatalysts with higher energy facets exposed usually possess greatly enhanced photocatalytic activities than single-phase catalysts, a novel Cu2O octadecahedron/TiO2 quantum dot (Cu2O-O/TiO2-QD) p-n heterojunctions composite was designed and synthesized in this study. Cu2O octadecahedra (Cu2O-O) with {110} facets and {100} facets exposed were synthesized first, then highly dispersed TiO2 quantum dots (TiO2-QDs) were loaded on Cu2O-O by the precipitation of TiO2-QDs sol in the presence of absolute ethanol. The morphology, crystal structure, chemical composition, optical properties, photocatalytic activity, and stability of Cu2O-O/TiO2-QD heterojunctions were characterized and investigated. It was found that TiO2-QDs were firmly anchored on Cu2O-O single crystals with good dispersibility. The Cu2O-O/TiO2-QD heterojunctions with partial coverage of TiO2-QDs showed a strong absorbance of visible light and exhibited an effective transfer of photoexcited electrons. The degradation of methyl orange (MO) under visible light irradiation indicated that the photocatalytic activity of Cu2O-O/TiO2-QD heterojunctions was significantly enhanced compared with that of Cu2O-O. This Cu2O-O/TiO2-QD heterojunctions composite exhibited high stability in MO degradation process and after storage in air. The high visible light photocatalytic activity and good stability were attributed to high utilization of light, effective separation of photoexcited electron-hole pairs, and instant scavenging of holes in the unique heterojunction structure.
authors.affiliation: School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Xu
authors.affiliation: School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Gao
authors.affiliation: School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.
authors.forename: Zhenduo
authors.initials: Z
authors.lastname: Cui
authors.affiliation: School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.|Tianjin Key Laboratory of Composite and Functional Materials , Tianjin 300072, China.
authors.forename: Yanqin
authors.initials: Y
authors.lastname: Liang
authors.affiliation: School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.|Tianjin Key Laboratory of Composite and Functional Materials , Tianjin 300072, China.
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Li
authors.affiliation: School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.|Tianjin Key Laboratory of Composite and Functional Materials , Tianjin 300072, China.
authors.forename: Shengli
authors.initials: S
authors.lastname: Zhu
authors.affiliation: School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.|Tianjin Key Laboratory of Composite and Functional Materials , Tianjin 300072, China.
authors.forename: Xianjin
authors.initials: X
authors.lastname: Yang
authors.affiliation: Key Laboratory for Micro-/Nano-Optoelectronic Devices of the Ministry of Education, School of Physics and Electronics, Hunan University , Changsha 410082, China.|Institute for Superconducting and Electronic Materials, University of Wollongong , Wollongong, New South Wales 2522, Australia.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Ma
keywords: Cu2O octadecahedron/TiO2 quantum dot; heterojunctions; higher energy facets; photocatalytic activity; photoexcited electron−hole pairs; stability