Exclusive Bridged ^* OCHO Pathway Activated by Phenol‐Quinone Conversion on the Surface of Cu(OH) ₂ for Highly Selective Formate Production in CO ₂ Electroreduction

Abstract Copper‐based electrocatalysts with exceptional selectivity for single product during the carbon dioxide reduction reaction (CO 2 RR) have attracted widespread attention. However, achieving precise control over reaction pathways and suppression of competing byproducts remains a critical challenge. Here, phenolic 2,3,6,7,10,11‐hexahydroxytriphenyl (HHTP) is strategically anchored on Cu(OH) 2 to construct CuHHTP/Cu(OH) 2 catalysts, where surface phenol‐to‐quinone conversion modulates CO 2 adsorption configuration, enabling a distinct reaction pathway to formate (HCOOH) production during CO 2 RR. Mechanistic studies demonstrate that the epitaxial phenolic HHTP linker undergoes interconversion to an oxidized, deprotonated quinone form, which can act as an electron‐withdrawing modulator. Owing to this dynamic redox behavior, electron delocalization toward the quinones epitaxial HHTP linker, charge density of the Cu centers reduces, enhancing their affinity for electronegative oxygen atoms and favoring the formation of the symmetric and bidentate‐bridged *OCHO intermediate over *COOH. In situ infrared spectroscopy and theoretical calculations further elucidate the specificity and enhance the thermodynamic favorability of the *OCHO formation pathway. Optimal CuHHTP/Cu(OH) 2 delivers a high formate Faradaic efficiency of 88.8% with a current density of 65.6 mA cm − 2 at −1.4 V versus RHE, retaining 83.0% efficiency after 66 h continuous test. This study presents a novel strategy based on intermolecular conversion on Cu‐based catalysts for highly selective CO 2 RR catalysts.