Molecularly Engineered Self-Assembled Molecular Layer for pH-Tolerant CO₂ Electroreduction With Enhanced Activity and...

The electrochemical CO₂ reduction is crucial for achieving carbon neutrality, wherein the catalytic performance is governed not only by the intrinsic catalytic activity but also by the microenvironment of the triple-phase interface. In this study, a self-assembled molecular (SAM) of trimethoxy(3,3,3-trifluoropropyl)silane (TFTPS) is constructed on a traditional Bi-based electrocatalyst to enhance its catalytic efficiency. The modified catalyst delivers a high current density of 800 mA cm^-2 and maintains a formate Faradaic efficiency of up to 95% across a wide pH range. Notably, it also exhibits an excellent long-term durability of 250 h in a membrane electrode assembly system. Density functional theory calculations and classical molecular dynamics simulations reveal that this hydrophobic SAM possesses three key functions: (i) it maintains interfacial hydrophobicity to reduce H⁺ activity and prevent electrode flooding; (ii) it stabilizes a relatively higher oxidation state on the catalyst surface, thereby enhancing *OCHO adsorption; and (iii) it facilitates CO₂ mass transfer and local enrichment. These findings are further supported by in situ x-ray diffraction and spectroscopic measurements. Overall, this study proposes a molecular self-assembly strategy for optimizing tri-phase interfaces in electrocatalysis, which could drive advances in energy conversion technologies.