Catalytic hydrogenation of 2,3,5-trimethylbenzoquinone over Pd nanoparticles confined in the cages of MIL-101(Cr)

• Organic moiety and confined cages of MIL-101(Cr) improve Pd dispersion.
• Highly dispersed Pd nanoparticles with uniform size in the cages of MIL-101(Cr).
• Optimal Pd/MIL-101(Cr) much superior to Pd/C in terms of activity and stability.
• Development of highly efficient Pd/MIL-101(Cr) catalysts in the hydrogenation.

A series of Pd@MIL-101(Cr) catalysts with different Pd loadings were prepared by incorporating Pd nanoparticles into the highly porous and hydrothermally stable metal–organic framework MIL-101(Cr) via an incipient-wetness impregnation method and then characterized by XRD, N2 adsorption, CO chemisorption, XPS, and TEM techniques as well as by the elemental analysis. These prepared catalysts were applied in the catalytic hydrogenation of 2,3,5-trimethylbenzoquinone (TMBQ) to 2,3,5-trimethylhydroquinone (TMHQ) in a high-pressure batch reactor. The results reveal that the intrinsic activity of the MIL-101(Cr)-based catalysts is closely related to the Pd loading in MIL-101(Cr) and 2.0 wt.% Pd/MIL-101(Cr), in which Pd nanoparticles mainly within a range of 2–3 nm in diameter are confined in the mesoporous cages of MIL-101(Cr), shows the highest catalytic activity and selectivity with excellent reusability among the catalysts investigated, much superior to activated carbon supported Pd catalysts.

Pd/MIL-101(Cr) catalysts are highly efficient in the selective hydrogenation of 2,3,5-trimethylbenzoquinone to 2,3,5-trimethylhydroquinone.Figure optionsDownload as PowerPoint slide