Ultrathin two-dimensional triptycence-based metal-organic framework for highly selective CO2 electroreduction to CO

Efficient CO2 reduction reaction (CO2RR) is one of the important topics in energy and environment field, but improving the electrochemical selectivity of specific product is a great challenge. Herein, we reported a unprecedented two-dimensional (2D) metal−organic framework with CuO4 unit (denoted as Cu-HHTT, HHTT = 9,10-dihydro-9,10-[1,2]benzenoanthracene-2,3,6,7,14,15-hexaol) as the electrocatalyst for CO2RR. Cu-HHTT exhibits high performance for CO2RR to produce CO, namely Faradaic efficiency of 96.6% toward CO with a current density of 18 mA/cm2 at the potential of −0.6 V vs. RHE. Density function theory reveals that the desorption of CO species exhibits a lower energy barrier than that of hydrogenation of *CO intermediate, resulting in CO as the main product instead of alcohols or hydrocarbons.