Carbon-Supported Gold Nanocatalysts: Shape Effect in the Selective Glycerol Oxidation

Gold nanoparticles were supported on two types of carbon nanofibres with different degree of graphitisation. The investigation of these materials with an aberration-corrected transmission electron microscope showed that the degree of the surface graphitisation strongly influences the structures of the supported gold particles. The more ordered graphitic layers of the carbon nanofibre surface led to Au particles more preferred to immobilise on their {1 1 1} plane, exhibiting more facet area. In contrast, disordered carbon nanofibre surfaces led to random orientation of supported particles. The different shape of similarly sized Au nanoparticles allowed determining the effect of support surface structures on the selectivity of the catalyst in the liquid-phase oxidation of glycerol, highlighting the higher C3 product selectivity on the {1 1 1} surface. Based on these results, we could also gain new insight in the effect of Au nanoparticle size on the selectivity in the liquid-phase oxidation of glycerol, that is, larger particles were more selective toward C3 products than the smaller ones.