Fe-Based MOFs for Photocatalytic CO2 Reduction: Role of Coordination Unsaturated Sites and Dual Excitation Pathways

详细信息    查看全文

• 作者：Dengke Wang ; Renkun Huang ; Wenjun Liu ; Dengrong Sun ; Zhaohui Li
• 刊名：ACS Catalysis
• 出版年：2014
• 出版时间：December 5, 2014
• 年：2014
• 卷：4
• 期：12
• 页码：4254-4260
• 全文大小：299K
• ISSN：2155-5435

文摘

The utilization of solar energy for the conversion of CO₂ into valuable organic products is one of the best solutions to solve the problems of global warming and energy shortage. The development of photocatalysts capable of reducing CO₂ under visible light, especially those containing earth-abundant metals, is significant. Herein we report that a series of earth-abundant Fe-containing MOFs (MIL-101(Fe), MIL-53(Fe), MIL-88B(Fe)) show photocatalytic activity for CO₂ reduction to give formate under visible light irradiation. The direct excitation of the Fe鈥揙 clusters in these MOFs induces the electron transfer from O2鈥?/sup> to Fe³⁺ to form Fe²⁺, which is responsible for the photocatalytic CO₂ reduction. Among the three investigated Fe-based MOFs, MIL-101(Fe) showed the best activity due to the existence of the coordination unsaturated Fe sites in its structure. All three amine-functionalized Fe-containing MOFs (NH₂-MIL-101(Fe), NH₂-MIL-53(Fe) and NH₂-MIL-88B(Fe)) showed enhanced photocatalytic activity in comparison to the unfunctionalized MOF, due to the existence of dual excitation pathways: i.e., excitation of an NH₂ functionality followed by an electron transfer to the Fe center in addition to the direct excitation of Fe鈥揙 clusters.

Keywords:

photocatalytic CO₂ reduction; visible light; metal鈭抩rganic frameworks; coordination unsaturated sites; dual excitation pathway