3D Cu Microbuds for Electrocatalytic CO Reduction Reaction

Abstract Cu‐based materials can electrocatalytically reduce CO 2 or CO into high‐value‐added multi‐carbon (C 2+ ) products. The features, including morphology, crystal plane, etc., have a great influence on their electrocatalytic performance. Herein, the 3D Cu microbuds (3D Cu MBs) are finely synthesized with enriched grain boundaries by controlling the reaction temperature, time, and pH. The obtained Cu MBs can work as an efficient catalyst for electrocatalytic CO reduction reaction (eCORR) in a flow cell. As compared to the commercial micron Cu, Cu MBs exhibit a significantly higher C 2+ product selectivity (≈83% at −0.58 V vs reversible hydrogen electrode‐RHE), higher partial current density (410 mA cm −2 ), and a lower overpotential. The typical 3D hierarchical structure and polycrystalline feature endow the Cu MBs with abundant active grain boundaries for eCORR to form C 2+ products. This study offers a new insight into the crystalline‐controlled synthesis of 3D Cu catalyst for CO electrolysis.