Optimizing electrochemical alcohol oxidation reactions via defect-rich CoFe-layered double hydroxide

Abstract

The conversion of ethanol to acetic acid serves as a benchmark reaction for alcohol oxidation. The electrochemical oxidation of alcohols coupled with H₂ generation has garnered considerable attention owing to its promising potential in reducing fossil energy consumption. In this study, we report the design and fabrication of CoFe-LDH with metal and oxygen defects (CoFe-LDH-D) through an electrochemical alkali activation process. During the activation, lattice Al atoms transform into soluble Al(OH)₄⁻, leading to the formation of metal vacancies and oxygen defects. The resultant CoFe-LDH-D exhibits a high electrochemical active surface area and an increased coverage of Co atoms (τ*), which facilitates efficient charge and ion transfer. Consequently, CoFe-LDH-D achieves a current density of 100 mA cm⁻² for the ethanol oxidation reaction (EOR) at a potential of 1.392 V vs. RHE, presenting a 67 mV negative shift compared to CoFe-LDH. In situ Raman spectroscopy, DFT calculations and control experiments reveal that the Co atoms serve as the active sites, and the defect-rich structure reduces the reaction energy barrier for dehydrogenation during the EOR.