Al-Doped Octahedral CuO Nanocrystal for Electrocatalytic CO Reduction to Produce Ethylene.

Ethylene is an ideal CO product in an electrocatalytic CO reduction reaction (CORR) with high economic value. This paper synthesised Al-doped octahedral CuO (Al-CuO) nanocrystal by a simple wet chemical method. The selectivity of CORR products was improved by doping Al onto the surface of octahedral CuO. The Al-CuO was used as an efficient electrocatalyst for CORR with selective ethylene production. The Al-CuO exhibited a high % Faradic efficiency (FE) of 44.9% at -1.23 V (vs. RHE) in CO saturated 0.1 M KHCO electrolyte. Charge transfer from the Al atom to the Cu atom occurs after Al doping in CuO, optimizing the electronic structure and facilitating CORR to ethylene production. The DFT calculation showed that the Al-CuO catalyst could effectively reduce the adsorption energy of the *CHCOH intermediate and promote the mass transfer of charges, thus improving the FE. After Al doping into CuO, the center of d orbitals shift positively, which makes the d-band closer to the Fermi level. Furthermore, the density of electronic states increases due to the interaction between Cu atoms and intermediates, thus accelerating the electrochemical CO reduction process. This work proved that the metal doping strategy can effectively improve the catalytic properties of CuO, thus providing a useful way for CO cycling and green production of CH.