Engineering vacancy and hydrophobicity of spherical coral-like CuO catalyst for effective electrochemical CO2 reduction to ethylene

Electrochemical carbon dioxide reduction (ECR) to ethylene by using renewable energy is a viable way to tackle the global climate change, and beneficial to facilitate closing the carbon cycle . Herein, a sulfur-doped spherical coral-like CuO (S-CuO) catalyst was facile synthesized, which is enabling efficient conversion CO 2 -to-C 2 H 4 . The obtained 5% S-CuO can reach the Faradaic efficiency (C 2 H 4 ) of 48.4% with a current density of 15 mA cm −2 at -1.3 V vs. RHE, which maintained stability over 20 h in 0.1 M KHCO 3 electrolyte. XPS , SEM, TEM, and XRD were applied in the characterization of the materials. EPR, CO 2 adsorption measurements and density functional theory calculations results indicate that the incorporation of S can promote CO 2 adsorption, activation and the formation of *COOH intermediate, which is boosting CO 2 conversion enabling the high selectivity to C 2 H 4 . Compared to unmodified CuO, electrocatalytic studies show that the greatly increased C 2 H 4 activity on S-CuO is because of the fast electron transfer . Meanwhile, the contact angle measurement reveals the excellent selectivity is derived from the suppression of the hydrogen evolution reaction after the S doping.