Improvement of carbon dioxide electroreduction by crystal surface modification of ZIF-8

Abstract

Metal–organic frameworks (MOFs) possess high CO₂ adsorption properties and are considered to be a promising candidate for the electrochemical carbon dioxide reduction reaction (eCO₂RR). However, their insufficient selectivity and current density constrain their further exploration in the eCO₂RR. In this work, by introducing a very small proportion of 2,5-dihydroxyterephthalic acid (DOBDC) into ZIF-8, a surface modified ZIF-8-5% catalyst was synthesized by a post-modification method, exhibiting enhanced selectivity (from 56% to 79%) and current density (from −4 mA cm⁻² to −10 mA m⁻²) compared to ZIF-8. Density functional theory (DFT) calculations further demonstrate that the boosted eCO₂RR performance on ZIF-8-5% could be attributed to the improved formation of the *COOH intermediate stemming from successful DOBDC surface modification. This work opens a new path for improving the catalytic properties of MOFs via their surface modification.