Ag-triggered Co 4+ active sites enable OH* nucleophilic attack for efficient electrocatalytic alcohols to acids

Abstract

Selective oxidation of primary alcohols to carboxylic acids is widely employed transformation in organic chemistry. However, the intrinsic mechanism by which R(Ph)-OH (R is an alkyl or phenyl) in alcohols undergoes dehydrogenation to form oxygenrich acids remains elusive. Here, we demonstrate an efficient interface cooperative structure (Ag/Co(OH)2) as electrocatalyst. Ag/Co(OH)2 significantly lowers the energy barrier of the rate-determining step (Ph-CHO* + OH* → Ph-CH(OH)2*) to 0.78 eV and enhances the chemisorption of Ph-CHO intermediates to -0.89 eV, both superior to Co(OH)2 (ΔG = 1.22 eV, Gads = -0.72 eV), with the Faraday efficiency of carboxylic acids reached 99.6% under mild conditions. Kinetic studies reveal the formation of Co⁴⁺-O species on the composite surface, promoting the capture of OH*. Furthermore, Ag/Co(OH)₂ also demonstrates excellent Faradaic efficiency (ranging from 41.48% to 88.73%) in the oxidation of methanol, furfuryl alcohol, ethylene glycol, and 5-hydroxymethylfurfural to their corresponding carboxylic acids. This work provides a new idea for designing efficient and stable electrocatalytic carboxylic acid synthesis catalysts.