Graphdiyne as an Electron Modifier for Boosting Electrochemical Production of Adipic Acid

Abstract

Adipic acid (AA) is a crucial feedstock for nylon polymers, and is industrially produced by thermal oxidation of cyclohexanone/cyclohexanol mixture (KA oil). However, this process consumes large quantities of corrosive nitric acid as oxidants, while emits ozone-depleting greenhouse gas N₂O. Here, an electrocatalytic strategy for selective oxidation of KA oil to AA coupled with H₂ evolution over a Co₃O₄/graphdiyne cooperative catalyst (Co₃O₄/GDY) is reported. The Co₃O₄/GDY displays high electrooxidation activity of KA oil to AA (100 mA cm⁻² at ≈1.5 V vs RHE), outperforming all the reported findings. Detailed ex situ and in situ experimental studies, theoretical calculations, and molecular dynamic simulations reveal that GDY not only facilitates the enrichment of cyclohexanone on the catalyst surface in aqueous medium, but also upshifts the d-band center of Co sites, strengthening the adsorption/activation of cyclohexanone. This study offers a green route for AA synthesis and proposes a GDY interface engineering strategy for efficient electrooxidation.