Toward High-Performance CO2 -to-C2 Electroreduction via Linker Tuning on MOF-Derived Catalysts.

Abstract

Copper (Cu)-based metal-organic frameworks (MOFs) and MOF-derived catalysts are well studied for electroreduction of carbon dioxide (CO2 ); however, the effects of organic linkers for the selectivity of CO2 reduction are still unrevealed. Here, a series of Cu-based MOF-derived catalysts is investigated with different organic linkers appended, named X-Cu-BDC (BDC=1,4-benzenedicarboxylic acid, X=NH2 , OH, H, F, and 2F). It is found that the linkers affect the faradaic efficiency (FE) for C2 products with an order of NH2 <OH<bare Cu-BDC<F<2F, thus tuning the FEC2 :FEC1 ratios from 0.6 to 3.8. As a result, the highest C2 FE of ≈63% at a current density of 150mAcm-2 on 2F-Cu-BDC derived catalyst is achieved. Using operando Raman measurements, it is revealed that the MOF derives to Cu2 O during eCO2 RR but organic linkers are stable. The fluorine group in organic linker can promote the H2 O dissociation to *H species, further facilitating the hydrogenation of *CO to *CHO that helps CC coupling.