LAUSR

Purposefully developing crystalline materials at molecular level to improve the selectivity of electroreduction CO 2 to CH 4 is still rarely studied. Herein, we designed and synthesized a single crystal of copper(II) complex with hydroxyl groups, namely 5,10,15,20-tetrakis(3,4-dihydroxyphenyl)porphyrin copper(II) (Cu-PorOH), which can serve as a highly efficient heterogeneous electrocatalyst for electroreduction CO 2 toward the production of CH 4 . In 0.5 M KHCO 3 , Cu-PorOH gives a high Faradaic efficiency of 51.3% for CH 4 and drives a partial current density of 23.2 mA cm -2 at -1.5 V versus the reversible hydrogen electrode in H-cell. The high performance is greatly contributed by the hydroxyl groups in Cu-PorOH, which can not only form stable three-dimensional frameworks through hydrogen-bonding interactions, but also can stabilize the intermediate species by hydrogen bonds supported by density functional theory calculations. This work provides an effective avenue in exploring crystalline catalysts for CO 2 reduction at molecular level .