Tuning Internal Strain in Metal-Organic Frameworks via Vapor Phase Infiltration for CO2 Reduction

Fan Yang; Wenhui Hu; Chongqing Yang; Margaret Patrick; Andrew L Cooksy; Jian Zhang; Jeffery A Aguiar; Chengcheng Fang; Yinghua Zhou; Ying Shirley Meng; Jier Huang; Jing Gu

doi:10.1002/anie.202000022

Tuning Internal Strain in Metal-Organic Frameworks via Vapor Phase Infiltration for CO₂ Reduction

Angew Chem Int Ed Engl. 2020 Mar 9;59(11):4572-4580. doi: 10.1002/anie.202000022. Epub 2020 Jan 29.

Authors

Fan Yang¹, Wenhui Hu², Chongqing Yang³, Margaret Patrick¹, Andrew L Cooksy¹, Jian Zhang³, Jeffery A Aguiar⁴, Chengcheng Fang⁵, Yinghua Zhou^{1

6}, Ying Shirley Meng⁵, Jier Huang², Jing Gu¹

Affiliations

¹ Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, USA.
² Department of Chemistry, Marquette University, Milwaukee, WI, 53201, USA.
³ The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
⁴ Nuclear Materials Department, Idaho National Laboratory, 2525 Fremont Avenue, Idaho Falls, ID, 83415, USA.
⁵ Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, 92093, USA.
⁶ The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241000, China.

PMID: 31914215
DOI: 10.1002/anie.202000022

Abstract

A gas-phase approach to form Zn coordination sites on metal-organic frameworks (MOFs) by vapor-phase infiltration (VPI) was developed. Compared to Zn sites synthesized by the solution-phase method, VPI samples revealed approximately 2.8 % internal strain. Faradaic efficiency towards conversion of CO₂ to CO was enhanced by up to a factor of four, and the initial potential was positively shifted by 200-300 mV. Using element-specific X-ray absorption spectroscopy, the local coordination environment of the Zn center was determined to have square-pyramidal geometry with four Zn-N bonds in the equatorial plane and one Zn-OH₂ bond in the axial plane. The fine-tuned internal strain was further supported by monitoring changes in XRD and UV/Visible absorption spectra across a range of infiltration cycles. The ability to use internal strain to increase catalytic activity of MOFs suggests that applying this strategy will enhance intrinsic catalytic capabilities of a variety of porous materials.

Keywords: CO2 reduction; internal strain; metal-organic frameworks; vapor-phase infiltration.

Abstract

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