Carboxylated graphene–TiO2 hybrids as multifunctional materials: from photocatalysis to peroxidase alternatives

Abstract

We synthetized hybrid materials with multifunctional properties by coupling graphene nanoplatelets (GNP) modified with carboxylic groups to titanium dioxide (TiO₂) nanoparticles (NPs) and tested them both as photocatalysts to promote pollution abatement and as tracers of the presence of a model antigen (bovine serum albumin, BSA) in immunochemical assays. The presence of carboxylic groups proved to be crucial in both applications: they improved TiO₂ photocatalytic activity by the interaction between the carboxylic groups on the GNP surface and the hydroxyl groups on TiO₂ surface, and allowed for covalently binding the material to BSA. The photoactivity of the materials was exploited for the oxidation of 3,3′,5,5′-tetramethylbenzidine for immunochemical applications.