Dual-Anion-Stabilized Cu δ+ Sites in Cu 2 (OH) 2 CO 3 for High C 2+ Selectivity in the CO 2 Electroreduction Reaction.

The excessive emission of CO 2 has aroused increasingly serious environmental problems. Electrochemical CO 2 reduction reaction (CO 2 RR) is an effective way to reduce CO 2 concentration and simultaneously produce highly valued chemicals and fuels. Cu δ+ species are regarded as promising active sites to obtain multi-carbon compounds in CO 2 RR, however, they are easily reduced to Cu 0 during the reaction and fail to retain the satisfying selectivity for C 2+ products. Herein, via a one-step method, we synthesize Cu 2 (OH) 2 CO 3 microspheres composed of nanosheets, which has achieved a superior Faraday efficiency for C 2+ products as high as 76.29 % at -1.55 V vs. RHE in an H cell and 78.07 % at -100 mA cm -2 in a flow cell. Electrochemical measurements, in situ Raman spectra and attenuated total reflectance infrared spectra (ATR-IR) as well as the theoretic calculation unveil that, compared with Cu(OH) 2 and CuO, the dual O-containing anionic groups (OH - and CO 3 2- ) in Cu 2 (OH) 2 CO 3 can effectively stabilize the Cu δ+ species, promote the adsorption and activation of CO 2 , boost the coverage of *CO and the coupling of *CO-*COH, thus sustain the flourishment of C 2+ products.