Modulating the CuO Photoelectrode/Electrolyte Interface with Bilayer Surfactant Simulating Cell Membranes for Boosting Photoelectrochemical CO Reduction.

The low solubility of CO molecules and the competition of the hydrogen evolution reaction (HER) in aqueous electrolytes pose significant challenges to the current photoelectrochemical (PEC) CO reduction reaction. In this study, inspired by the bilayer phospholipid molecular structure of cell membranes, we developed a CuO/Sn photocathode that was modified with the bilayer surfactant DHAB for achieving high CO permeability and suppressed HER. The CuO/Sn/DHAB photocathode stabilizes the *OCHO intermediate and facilitates the production of HCOOH. Our findings show that the Faradaic efficiency (FE) of HCOOH by the CuO/Sn/DHAB photoelectrode is 83.3%, significantly higher than that achieved with the CuO photoelectrode (FE = 30.1%). Furthermore, the FE produced by the CuO/Sn/DHAB photoelectrode is only 2.95% at -0.6 V vs RHE. The generation rate of HCOOH by the CuO/Sn/DHAB photoelectrode reaches 1.52 mmol·cm·h·L at -0.7 V vs RHE. Our study provides a novel approach for the design of efficient photocathodes for CO reduction.