The Catalytic Performance And Chemical Modification Of Oxygen Groups On Graphene Oxide

As a two-dimensional carbon nanomaterial, graphene oxide(GO) has plenty of oxygen groups and exhibits unique physicochemical properties. It can be reduced to obtain graphene with large-scale production. Up to now, the GO with carboxyl and hydroxyl groups has been modified through various chemical methods and shows great potential in catalyst and surface modification.Owing to the catalytic ability of carboxyl groups on its edges, the graphene oxide could be used in the preparation of Se nanoparticles. The gas-solid reaction between H2 Se gas and GO powder could result in the successful synthesis of Se nanoparticles, which mainly distribute on the GO edges and wrinkles. With the increasing of reaction time, the sizes of these nanoparticles also increased. The reagents in this reaction were H2 Se gas and O2, and the carboxyl groups on GO powder exhibited a good catalytic performance. In addition, the modification of carboxyl groups by amidation reaction was also investigated. Through the grafting-from method, the poly(amide amine) dendrimer modified graphene oxide(GO–PAMAM) was successfully prepared. With terminal amino groups(–NH2), the GO-PAMAMA nanocompound exhibits good dispersion and excellent adsorption ability to heavy metal ions in water, and shows broad applications in water treatment of industrial waste.After modification of hydroxyl groups on GO, the graphene oxide could be also applied in biochemistry, especially in the immobilization of enzyme and antibody. The hydroxyl groups could react with(3-mercaptopropyl) trimethoxysilane, and the product with terminal thiol groups could be further oxidized to immobilize the lipase. The GO combines the long carbon chain by covalent reaction and has little influence on the enzyme configuration. For the hydrolysis reaction of p-nitrophenylpalmitate, the immobilized enzyme exhibits 93.4% catalytic activity of the free enzyme. Though the pH stability of GO-lipase is similar with that of the free lipase, its thermostability is better than the free lipase. After ten reaction cycles, the GO-lipase remains about 69.9% of the preliminary catalytic ability. The good reusability makes the GO-lipase a promising material in enzyme engineering. Besides, the hydroxyl groups could covalently react with the 3-phosphonopropionic acid through bidentate way by using the tethering by aggregation and growth(T-BAG) method. The modification of the GO surfaces provides the compound the ability to immobilize the antibody IgG and further capture its specific antigen with a high efficiency(80.0%). The compound shows great potential in protein capture.