Laser synthesis of Pt, Pd, CoO and Pd–CoO nanoparticle catalysts supported on graphene

We have developed a facile laser reduction method for the synthesis of transition metal nanoparticle catalysts supported on reduced graphene oxide (RGO) sheets. Using 532 or 355 nm laser irradiation of a mixture of graphene oxide and metal ion precursors in water, we report the photocatalytic reduction of the metal ions simultaneously with the partial reduction of GO, and the synthesis of metal nanoparticle catalysts well-dispersed and supported on the reduced GO. The Pd–CoO composite nanoparticles were found to have significantly enhanced activity for CO oxidation over both the Pd and the CoO catalysts. The simple synthesis method without chemical reducing agents, the formation of alloy nanoparticles with variable catalyst loading and composition, and the low cost of GO could enhance the commercial viability of these supported catalysts.