Au nanoparticles supported on Cr-based metal-organic framework as bimetallic catalyst for selective oxidation of cyclohexane to cyclohexanone and cyclohexanol

Two bimetallic catalysts Au/MIL-53(Cr) and Au/MIL-101(Cr) were prepared by urea deposition–precipitation. The catalytic performances of these catalysts were investigated via selective oxidation of cyclohexane to cyclohexanone and cyclohexanol by molecular oxygen in the absence of solvent and initiator. It is believed that framework Cr ions are effective catalytic sites, which accounts for that Au/MIL-53(Cr) and Au/MIL-101(Cr) exhibit superior catalytic performance. The confinement effect of MIL-101(Cr) cages to Au nanoparticles results in < 2 nm Au particles, which accounts for that Au/MIL-101(Cr) presents higher selectivity than Au/MIL-53(Cr).

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► Cr-based MOFs were employed as supports for Au nanoparticles by urea-DP.
► Au/MIL-n (Cr) (n = 53,101) catalyze cyclohexane selective oxidation efficiently.
► Both framework Cr ions and Au nanoparticles are catalytic sites for the reaction.
► MIL-101(Cr) cages exhibit confinement effect to Au nanoparticles.