Reversing CO2 photoreduction selectivity from CO to near 100 % CH4 using cation vacancy-induced pair sites in thinned MOFs

Man Ou, Fenghong Bai, Caichao Ye, Wenfan Shao, Xiaojing Liu, Wenqing Zhang, Chaoran Dong, Jie Jin, Shipeng Wan, Yuhui Chen, Kan Zhang, Jong Hyeok Park

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Metal-organic frameworks (MOFs) with customizable components can photo-reduce CO2 into various products; however, tuning the distribution of these products through modification engineering remains challenging. In this study, we propose a novel bottom-up surfactant-assisted preorganization strategy to simultaneously disrupt inner Van der Waals forces and induce Ti cation vacancies in the well-known NH2-MIL-125 MOF. The resulting Ti-deficient NH2-MIL-125 nanosheets, featuring unpaired electrons on O atoms and residual Ti sites, not only significantly enhance photo-generated charge migration but also facilitate the further protonation of CO* to CHO* during CO2 photoreduction. Unlike NH2-MIL-125, which predominantly converts CO2 to CO, the Ti-deficient NH2-MIL-125 nanosheets achieve an impressive selectivity of 95.7 % for CH4 production, with an electron consumption rate of 51.0 mol·g−1·h−1 for the first time. This approach of creating metal-cation vacancies to synergistically modulate charge separation dynamics and catalytic reaction kinetics offers a new pathway to refine the activity and selectivity of multifaceted competitive catalytic reactions.

Original languageEnglish
Article number124938
JournalApplied Catalysis B: Environmental
Volume365
DOIs
StatePublished - 15 May 2025

Keywords

  • CO reduction
  • Cation vacancy
  • Metal-organic frameworks
  • Unpaired electrons

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