Tailoring Interlayer Microenvironment of 2D Layered Double Hydroxides for CO ₂ Reduction with Enhanced C ₂₊ Production

Abstract Both the physicochemical properties of catalytic material and the structure of loaded catalyst layer (CL) on gas diffusion electrode (GDE) are of crucial importance in determining the conversion efficiency and product selectivity of carbon dioxide reduction reaction (CO ₂ RR). However, the highly reducing reaction condition of CO ₂ RR will lead to the uncontrollable structural and compositional changes of catalysts, making it difficult to tailor surface properties and microstructure of the real active species for favored products. Herein, the interlayer microenvironment of copper‐based layered double hydroxides (LDHs) is rationally tuned by a facile ink solvent engineering, which affects both the surface characters and microstructure of CL on GDE, leading to distinct catalytic activity and product selectivity. According to series of in situ and ex situ techniques, the appropriate surface wettability and thickness of porous CL are found to play critical roles in controlling the local CO ₂ concentration and water dissociation steps that are key for hydrogenation during CO ₂ RR, leading to a high Faradaic efficiency of 75.3% for C ₂₊ products and a partial current density of 275 mA cm ⁻² at −0.8 V versus RHE. This work provides insights into rational design of efficient electrocatalysts toward CO ₂ RR for multi‐carbon generation.