Dicopper(I) Sites Confined in a Single Metal–Organic Layer Boosting the Electroreduction of CO<sub>2</sub> to CH<sub>4</sub> in a Neutral Electrolyte
Jin‐Meng Heng, Haolin Zhu, Zhen‐Hua Zhao, Can Yu, Pei‐Qin Liao, Xiao‐Ming Chen
Abstract
It is challenging and important to achieve high performance for an electrochemical CO 2 reduction reaction (eCO 2 RR) to yield CH 4 under neutral conditions. So far, most of the reported active sites for eCO 2 RR to yield CH 4 are single metal sites; the performances are far below the commercial requirements. Herein, we reported a nanosheet metal–organic layer in single-layer, namely, [Cu 2 (obpy) 2 ] ( Cuobpy-SL, Hobpy = 1 H -[2,2′]bipyridinyl-6-one), possessing dicopper(I) sites for eCO 2 RR to yield CH 4 in a neutral aqueous solution. Detailed examination of Cuobpy-SL revealed high performance for CH 4 production with a faradic efficiency of 82(1)% and a current density of ∼90 mA cm –2 at −1.4 V vs . reversible hydrogen electrode (RHE). No obvious degradation was observed over 100 h of continuous operation, representing a remarkable performance to date. Mechanism studies showed that compared with the conventional single-copper sites and completely exposed dicopper(I) sites, the dicopper(I) sites in the confined space formed by the molecular stacking have a strong affinity to key C 1 intermediates such as *CO, *CHO, and *CH 2 O to facilitate the CH 4 production, yet inhibiting C–C coupling.