Hydrophobic perfluoroalkane modified metal?organic frameworks for the enhanced electrocatalytic reduction of CO ₂

The electrochemical reduction of CO2 to value-added chemicals would be an efficient way utilize and mitigate greenhouse gas emission. However, the associated competitive hydrogen evolution reaction (HER) in aqueous electrolytes usually leads poor selectivity for electroreduction reactions (CO2RR). Due their high specific surface areas tunable single active sites, metal-organic frameworks (MOFs) are considered as promising candidates CO2RR. Herein, Fe-porphyrin based Zr-MOF, PCN-222(Fe), was treated with perfluorocarboxylic acid afford hydrophobic Fn-PCN-222(Fe) (n = 5 7, n is number fluorine atoms perfluoroalkyl chain) improving CO2RR via inhibiting HER. Owing Fe sites were positioned a microenvironment, optimal F5-PCN-222(Fe) shows Faradic efficiency 97% toward production CO at ?0.7 V versus reversible electrode. Meanwhile, achieved turnover frequency value 3850 h?1 ?0.8 V, which almost 3.6 times higher than that PCN-222(Fe) surpassed most other reported MOFs. This study paves new improve HER by increasing hydrophobicity electrocatalysts.