Synthesis of few-layered graphene sheets as support of cobalt nanoparticles and its influence on CO hydrogenation

Abstract

We prepared few-layered reduced graphene oxide (rGO) as support in CO hydrogenation reaction. We investigated the graphene structure, mostly its electron donation effects to the cobalt particles, exploring the CO dissociation and the reaction results. Some modifications in the graphene synthesis method allowed the obtaining of a few-layered structure. No crystalline areas were detected. The prepared reduced graphene oxide was decorated with cobalt nanoparticles using the precipitation-deposition method (15% wt) in an alcoholic media. The catalyst was characterized before and after reaction by several techniques. XPS results revealed a higher concentration of Co2+ species at the surface and electrostatic interaction with the support. Diffuse Reflectance Infrared Fourier Transform Spectroscopy analysis (DRIFTS) suggested formate species formation on the catalyst surface and the absence of bridge-bonded adsorbed CO. The electronic interaction between cobalt nanoparticles and graphene affected carbon monoxide dissociation, preventing the electron backdonation from the active metal NPs to CO molecules.