Gold supported on graphene oxide/silica photocatalyst for hydrogen generation from formic acid

Abstract

Hydrogen gas has attracted a great deal of attention as a fuel due to its non-polluting combustion reaction. A wide variety of approaches have been employed to generate this green fuel with a remarkable concentration on photocatalytic pathways, in which a free source of energy is consumed for hydrogen evolution. Accordingly, we focused on construction of a photocatalyst of gold supported on graphene oxide–silicon dioxide (SiO2) for hydrogen generation through photocatalytic degradation of formic acid. It was demonstrated that the modification of SiO2 with graphene oxide and gold surprisingly extended photo-absorption of the semiconductor. The nanocomposite productively consumed photoelectrons for conversion of protons to hydrogen with turnover frequency of 539 h−1 at room temperature. This high activity of the nanocomposite was ascribed to the formation of simultaneous electron-rich and hole-rich centers in interfaces of graphene oxide–gold and graphene oxide–SiO2, respectively, which accelerated the process by both hydrogen generation in electron-doped sites and CO2 evolution in hole-doped platforms.