{"title":"Crystal-Defect-Induced Longer Lifetime of Excited States in a Metal-Organic Framework Photocatalyst to Enhance Visible-Light-Mediated CO<sub>2</sub> Reduction.","authors":"Zhifen Guo, Xin Liu, Yan Che, Hongzhu Xing","doi":"10.1021/acs.inorgchem.4c01738","DOIUrl":null,"url":null,"abstract":"<p><p>We report the structural defects in Zr-metal-organic framework (MOFs) for achieving highly efficient CO<sub>2</sub> reduction under visible light irradiation. A series of defective Zr-MOF-<i>X</i> (<i>X</i> = 160, 240, 320, or 400) are synthesized by acid-regulated defect engineering. Compared to pristine defect-free Zr-MOF (NNU-28), N<sub>2</sub> uptake increases for Zr-MOF-<i>X</i> synthesized with the HAc modulator, producing a larger pore space and Brunauer-Emmett-Teller surface area. The pore size distribution demonstrates that defective Zr-MOF-<i>X</i> exhibits mesoporous structures. Electrochemistry tests show that defective Zr-MOF-<i>X</i> possesses a more negative reduction potential and a higher photocurrent responsive signal than that of pristine NNU-28. Consequently, the defective samples exhibit a significantly higher efficiency in the photoreduction of CO<sub>2</sub> to formate. Transient absorption spectroscopies manifest that structural defects modulate the excited-state behivior of Zr-MOF-<i>X</i> and improve the photogenerated charge separation of Zr-MOF-<i>X</i>. Furthermore, electron paramagnetic resonance and in-suit X-ray photoelectron spectroscopy provide additional evidence of the high photocatalytic performance exhibited by defective Zr-MOF-<i>X</i>. Results demonstrate that structural defects in Zr-MOF-<i>X</i> also improve the charge transfer, producing abundant Zr(III) catalytically active sites, exhibiting a slower decay process than defect-free Zr-MOF. The long-lifetime Zr(III) species in defective Zr-MOF-<i>X</i> are fully exposed to a high-concentration CO<sub>2</sub> atmosphere, thereby enhancing the photocatalytic efficiency of CO<sub>2</sub> reduction.</p>","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Inorganic Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.inorgchem.4c01738","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
We report the structural defects in Zr-metal-organic framework (MOFs) for achieving highly efficient CO2 reduction under visible light irradiation. A series of defective Zr-MOF-X (X = 160, 240, 320, or 400) are synthesized by acid-regulated defect engineering. Compared to pristine defect-free Zr-MOF (NNU-28), N2 uptake increases for Zr-MOF-X synthesized with the HAc modulator, producing a larger pore space and Brunauer-Emmett-Teller surface area. The pore size distribution demonstrates that defective Zr-MOF-X exhibits mesoporous structures. Electrochemistry tests show that defective Zr-MOF-X possesses a more negative reduction potential and a higher photocurrent responsive signal than that of pristine NNU-28. Consequently, the defective samples exhibit a significantly higher efficiency in the photoreduction of CO2 to formate. Transient absorption spectroscopies manifest that structural defects modulate the excited-state behivior of Zr-MOF-X and improve the photogenerated charge separation of Zr-MOF-X. Furthermore, electron paramagnetic resonance and in-suit X-ray photoelectron spectroscopy provide additional evidence of the high photocatalytic performance exhibited by defective Zr-MOF-X. Results demonstrate that structural defects in Zr-MOF-X also improve the charge transfer, producing abundant Zr(III) catalytically active sites, exhibiting a slower decay process than defect-free Zr-MOF. The long-lifetime Zr(III) species in defective Zr-MOF-X are fully exposed to a high-concentration CO2 atmosphere, thereby enhancing the photocatalytic efficiency of CO2 reduction.
期刊介绍:
Inorganic Chemistry publishes fundamental studies in all phases of inorganic chemistry. Coverage includes experimental and theoretical reports on quantitative studies of structure and thermodynamics, kinetics, mechanisms of inorganic reactions, bioinorganic chemistry, and relevant aspects of organometallic chemistry, solid-state phenomena, and chemical bonding theory. Emphasis is placed on the synthesis, structure, thermodynamics, reactivity, spectroscopy, and bonding properties of significant new and known compounds.