CuMoRu ternary nanorods: synergy effect of metal elements enables efficient electrochemical CO2 reduction towards selective ethanol production

Abstract

Copper (Cu)-based alloy catalysts are capable of converting CO 2 to hydrocarbons and oxygenated compounds through electrochemical CO 2 reduction reaction (eCO 2 RR).However, it remains a great challenge to selectively obtain ethanol or ethylene among the C 2 products of eCO 2 RR. Herein, CuMoRu alloy nanorods catalysts were synthesized by a one pot wet chemistry method. Compared to Cu, CuRu and CuMo catalysts, CuMoRu is more efficiently to convert CO 2 to ethanol in eCO 2 RR.Theoretical calculation illustrates that Mo and Ru doping to Cu substrate leads to suppressed hydrogen evolution (HER), enhanced *CO production, and the formation of C 2 products occurs via CO-CHO pathway. Additionally, the stabilization of CH 2 CHO* and enhanced H 2 O dissociation also benefits ethanol production by breaking the scaling relationship. In a flow cell, CuMoRu displays a Faradaic efficiency of 63.0% and 51.8% for C 2 products and C 2 H 5 OH at -1.1 V vs. reversible hydrogen electrode (RHE), respectively, and the corresponding total and C 2 partial current density is 290 and 182.7 mA cm -2 in alkaline electrolyte. In-situ Raman spectroscopy demonstrated that the CuMoRu interface exhibits enhanced CO b (CO on bridging site) coverage and local pH, and the directly observed vibrational bands from *COCHO confirms the asymmetrical CO-CHO coupling mechanism. This work highlights the importance of alloying metal with Cu for selective production of C 2 products in eCO 2 RR.