Diels-Alder reaction is a useful method for modifying the surface of carbon materials.
activated carbon pellets suppliersIn this work, we functionalized activated carbon with a large number of carboxyl groups using the Diels-Alder reaction. Polyaromatic structure of activated carbon acted as a diene for addition of maleic anhydride (MA) that acted as a dienophile. Upon hydrolysis of the anhydride group in the adduct, vicinal carboxyl groups were formed. The formation of carboxyl groups by Diels-Alder reaction was proved by FTIR, solid-state
13C NMR, CO and CO
2 evolution from TPD and Boehm titration. Titration results showed that the number of carboxyl groups increased from 0.09 mmol g
−1 to 3.06 mmol g
−1. DFT calculation showed that the concave site of the armchair edge on carbon surface was the most favorable for the Diels-Alder addition. The formation of exo-adduct was preferred with a reaction energy (Δ
E) of −24 kJ mol
−1. The synthesized catalyst was tested for acid-catalyzed hydrolysis of cellobiose. The catalyst showed higher activity than a catalyst prepared by oxidation in the presence of air.
wanyang active carbon 
