title: Visible-Light Photoreduction of CO2 in a Metal-Organic Framework: Boosting Electron-Hole Separation via Electron Trap States.
abstract: 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-organic 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-hole separation efficiency. The presence of a deep electron trap state in PCN-222 effectively inhibits the detrimental, radiative electron-hole 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.
authors.forename: Hai-Qun
authors.initials: HQ
authors.lastname: Xu
authors.forename: Jiahua
authors.initials: J
authors.lastname: Hu
authors.affiliation: Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University , Fuzhou 350002, P. R. China.
authors.forename: Dengke
authors.initials: D
authors.lastname: Wang
authors.affiliation: Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University , Fuzhou 350002, P. R. China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Li
authors.forename: Qun
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Shu-Hong
authors.initials: SH
authors.lastname: Yu
authors.forename: Hai-Long
authors.initials: HL
authors.lastname: Jiang