A series of catalysts consisting of gold nanoparticles supported on MnO2 presenting different morphologies were synthesized and tested in the base-free oxidation of furfural. Ultra-small Au particles (less than 3 nm) were deposited on low (commercial MnO2) and high (NF, nanoflowers and NW, nanowires MnO2) surface area supports. High activity was observed for Au/MnO2-NF material with very high selectivity to furoic acid. The X-ray photoelectron spectroscopy (XPS) study confirmed the presence of

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... significant amount of highly active Auδ+ species on the surface of the Au/MnO2-NF catalyst. These species seem to be responsible for the high activity in oxidation of furfural under mild conditions (air as oxidant, 110 °C).