A novel MIL-101(Cr) acidified by silicotungstic acid and its catalytic performance for isomerization of n-heptane

Abstract

Abstract: 0.4%Pt/xSTA-MIL-101(Cr) metal-acid bifunctional catalysts were prepared by impregnation using STA-MIL-101(Cr) as the support. The synthesized samples were verified to exhibit a typical octahedral structure of MIL-101(Cr) and the pore structure were arranged orderly. The specific surface area of the samples was extremely high and the samples were micro-mesoporous composite materials. Silicotungstic acid could retain its Keggin structure in the 0.4%Pt/xSTA-MIL-101(Cr) samples and the catalyst possessed moderately strong Br?nsted acid sites. Besides, the dispersion of Pt particles in MIL-101(Cr) was relatively high. n-Heptane isomerization was first used as a probe to test the novel 0.4%Pt/xSTA-MIL-10(Cr) catalyst. Compared with the conventional silicate catalysts, the catalytic performance of 0.4%Pt/30wt%STA-MIL-101(Cr) was significantly improved with n-heptane conversion of 58.93% and iso-heptane selectivity of 95.68%, respectively, when the reaction time was 2 h at the reaction temperature of 260 oC. The catalyst could still maintain a relatively high catalytic performance during the reaction time of 5 h. Compared with the non-noble metal catalysts, the catalytic efficiency is relatively high. The mechanism model of n-heptane isomerization over 0.4%Pt/xSTA-MIL-101(Cr) catalyst was established.

Key words: MIL-101, Silicotungstic acid, n-Heptane, Isomerization, Platinum

References

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