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

Copper has long been the only element known to produce multicarbon (C₂₊) products from CO₂ through electrochemical pathways. However, its low kinetic barrier favors ethylene formation over C₂⁺ 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 C₂₊ alcohol selectivity and overall C₂₊ 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 C₂₊ product. We observed that the hollow Cu-Zn catalyst gives a Faradaic efficiency (FE) of 50.13% toward C₂₊ alcohol and an overall FE of 81% toward C₂₊ product at a very high current density of 300 mA cm^-2 in 1 M KHCO₃. 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.