Visible-Light Photoreduction of CO2 in a Metal鈥揙rganic Framework: Boosting Electron鈥揌ole Separation via Electron Trap States

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• 作者：Hai-Qun Xu ; Jiahua Hu ; Dengke Wang ; Zhaohui Li ; Qun Zhang ; Yi Luo ; Shu-Hong Yu ; Hai-Long Jiang
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：October 28, 2015
• 年：2015
• 卷：137
• 期：42
• 页码：13440-13443
• 全文大小：323K
• ISSN：1520-5126

文摘

It is highly desirable to convert CO₂ to valuable fuels or chemicals by means of solar energy, which requires CO₂ enrichment around photocatalysts from the atmosphere. Here we demonstrate that a porphyrin-involved metal鈥搊rganic framework (MOF), PCN-222, can selectively capture and further photoreduce CO₂ with high efficiency under visible-light irradiation. Mechanistic information gleaned from ultrafast transient absorption spectroscopy (combined with time-resolved photoluminescence spectroscopy) has elucidated the relationship between the photocatalytic activity and the electron鈥揾ole separation efficiency. The presence of a deep electron trap state in PCN-222 effectively inhibits the detrimental, radiative electron鈥揾ole recombination. As a direct result, PCN-222 significantly enhances photocatalytic conversion of CO₂ into formate anion compared to the corresponding porphyrin ligand itself. This work provides important insights into the design of MOF-based materials for CO₂ capture and photoreduction.