Selective oxidation of benzyl alcohol under solvent-free condition with gold nanoparticles encapsulated in metal-organic framework

•Highly dispersed Au NPs without deposition on the external surface or aggregation.•High activity and selectivity under solvent-free condition and atmospheric pressure.•Facilitated promotion effect of water due to the hydrophilic character of inner face.•Great stability and reusability of Au/UiO-66.

A metal organic framework encapsulated gold nanoparticles noted as Au/UiO-66 were developed through double solvents method. Highly dispersed Au nanoparticles were presented within the pores of metal-organic framework (MOF) UiO-66 without deposition of the nanoparticles on the external surface or aggregation. With benzyl alcohol as substrate, Au/UiO-66 exhibited excellent catalytic performance to afford benzaldehyde as the only product. The reactions which could be carried out under solvent-free conditions offered a green process with O2 of atmospheric pressure as oxidant. Water was proved to be beneficial for the reaction and the hydrophilic character of the MOF inner face facilitated its promotion effect greatly. The catalyst showed great stability and could be reused for at least eight times without obvious aggregation or leaching.

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