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

Abstract

The conversion of ethanol to acetic acid serves as a benchmark reaction for alcohols 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 the 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 reduce the reaction energy barrier for dehydrogenation during the EOR.