▎ 摘　　要

This paper reports a novel approach to the use of carbon, in the form of reduced graphene oxide, as a reducing agent for Au(III) chloride complex ions. This approach allows fabrication of a composite material Au@GO(r) in a single-step process. The reduction of Au(III) complex ions was performed using high pressure, 50 bar, and high temperature, 250?, reactor. The average diameter of obtained gold nanoparticles was below 3 nm. The advantage of the reduced graphene oxide as the reducing agent is its high surface area. This accelerates the reaction rate significantly. The greenness and sustainability of the process are assessed by green chemistry metrics and circularity indicators recently applied for the first time to a nanomaterial synthesis. As a key green metrics, atom economy (AE) measures the degree of the incorporation of reactant atoms into the final product and in the case of the research presented scoring 99%.