A Novel MIL-101(Cr) Acidified by Silicotungstic Acid and Its Catalytic Performance for Isomerization of n-Heptane

The 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 was arranged orderly. The specific surface area of the samples was extremely high and the samples were made of 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 Bronsted 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/30%STA-MIL-101(Cr) was significantly improved with a n-heptane conversion of 58.93% and an iso-heptane selectivity of 95.68%, respectively, under conditions covering a reaction time of 2 h and a reaction temperature of 260 degrees C. The catalyst could still maintain a relatively high catalytic performance after a reaction time of 5 h. Compared with the non-noble metal catalyst, the catalytic efficiency of 0.4%Pt/30%STA-MIL-101(Cr) is relatively high. The mechanism model of n-heptane isomerization over 0.4%Pt/xSTA-MIL-101(Cr) catalyst was established.

Automated summary

In this study, 0.4%Pt/xSTA-MIL-101(Cr) metal-acid bifunctional catalysts were prepared by impregnation using STA-MIL-101(Cr) as the support. The catalyst showed high catalytic performance in n-heptane isomerization and maintained relatively high catalytic activity. A mechanism model for the catalyst was also established.