Confining Reaction Intermediates in Oxide‐Derived Hollow Cu–Zn Bimetallic Catalyst Facilitates Selective Formation of C ₂₊ Alcohols from Electrochemical Carbon Dioxide Reduction

Abstract

Abstract Copper has long been the only element known to produce multicarbon (C 2+ ) products from CO 2 through electrochemical pathways. However, its low kinetic barrier favors ethylene formation over C 2 ⁺ alcohols at the selectivity‐determining step (SDS). Alloying Cu with secondary metals has been explored to shift selectivity toward alcohols, but these approaches often suffer from poor activity and selectivity. In this work, we probe the role of confinement of reaction intermediates in favoring C 2+ alcohol selectivity and overall C 2+ product in oxide‐derived hollow Cu–Zn bimetallic catalysts. From finite element method (FEM) simulation, it was observed that hollow catalyst increases the retention time of the reaction intermediates that favor the C─C coupling. Confinement gives rise to a two‐fold increment in the overall C 2+ product. We observed that the hollow Cu–Zn catalyst gives a Faradaic efficiency (FE) of 50.13% toward C 2+ alcohol and an overall FE of 81% toward C 2+ product at a very high current density of 300 mA cm −2 in 1 M KHCO 3 . DFT calculation shows that Zn affects selectivity determining step (SDS) and favors the formation of alcohol over ethylene. Various in situ techniques, such as X‐ray absorption spectroscopy, infrared spectroscopy, Raman spectroscopy, and differential electrochemical mass spectroscopy, were used to understand the active phase of the catalyst and mechanism in detail.