Photocatalytic Activity of Reduced Graphene Oxide-Gold Nanoparticle Nanomaterials: Interaction with Asphaltene and Conversion of a Model Compound

Asphaltenes are residual materials from the oil industry and are usually converted, after exhaustive distillation, into coke and asphalt. However, conversion of asphaltenes into more valuable raw materials, for instance, by photocatalytic cracking using suitable catalysts, would be a better, more economic option. To explore this idea, we combined the electronic and chemical properties of asphaltene and graphene derivatives with the plasmonic nature of gold nanoparticles. For this purpose, a hybrid material was generated in situ, containing reduced graphene oxide and gold nanoparticles (RGO@AuNP). Evaluation of the interaction between the hybrid material and asphaltenes by hyperspectral dark-field optical microscopy indicated the occurrence of charge transfer between the two species. Using 9-anthraldehyde (9-ATA) as a model compound for asphaltene, photocatalytic experiments performed with RGO@AuNP at room temperature, under visible light irradiation, revealed the formation of cyclic endoperoxides, which undergo further reactions, resulting in their cleavage, with 90% yield for the 9-ATA degradation.