Al-Doped Octahedral Cu(2)O Nanocrystal for Electrocatalytic CO(2) Reduction to Produce Ethylene

Ethylene is an ideal CO(2) product in an electrocatalytic CO(2) reduction reaction (CO(2)RR) with high economic value. This paper synthesised Al-doped octahedral Cu(2)O (Al–Cu(2)O) nanocrystal by a simple wet chemical method. The selectivity of CO(2)RR products was improved by doping Al onto the surface of octahedral Cu(2)O. The Al–Cu(2)O was used as an efficient electrocatalyst for CO(2)RR with selective ethylene production. The Al–Cu(2)O exhibited a high % Faradic efficiency (FE(C2H4)) of 44.9% at −1.23 V (vs. RHE) in CO(2) saturated 0.1 M KHCO(3) electrolyte. Charge transfer from the Al atom to the Cu atom occurs after Al doping in Cu(2)O, optimizing the electronic structure and facilitating CO(2)RR to ethylene production. The DFT calculation showed that the Al–Cu(2)O catalyst could effectively reduce the adsorption energy of the *CHCOH intermediate and promote the mass transfer of charges, thus improving the FE(C2H4). After Al doping into Cu(2)O, 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(2) reduction process. This work proved that the metal doping strategy can effectively improve the catalytic properties of Cu(2)O, thus providing a useful way for CO(2) cycling and green production of C(2)H(4).