Synthesis of Cu2O Octadecahedron/TiO2 Quantum Dot Heterojunctions with High Visible Light Photocatalytic Activity and High Stability

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• 作者：Xu Xu ; Zhonghui Gao ; Zhenduo Cui ; Yanqin Liang ; Zhaoyang Li ; Shengli Zhu ; Xianjin Yang ; Jianmin Ma
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：8
• 期：1
• 页码：91-101
• 全文大小：718K
• ISSN：1944-8252

文摘

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.