Preparation, Characterization of Pt-Re-MCM-41 Catalyst and Its Catalytic Conversion of Corncob for Producting Furan Compounds

A series of Pt-Re-MCM-41 catalysts with different metal loading were prepared by step impregnation method with MCM-41 as support. The physical and chemical properties of the catalysts were characterized by nitrogen adsorption-desorption, X-ray diffraction (XRD) and NH₃ temperature programmed desorption (NH₃-TPD). The effect of Pt-Re-MCM-41 on the catalytic conversion of corncob pyrolysis products to furan compounds, including its repeated using and regeneration performance, were discussed. The experimental results showed that Pt and Re were uniformly dispersed on the catalyst surface, and the structure and properties of MCM-41 were not changed after loading, but the surface area, pore volume of the catalyst decreased and the average pore diameter increased after loading. The catalyst system had weak acid and medium strong acid at the same time. After Pt and Re loading, the content of the two acid sites on the catalyst surface increased. The type and number of compounds detected by GC×GC were, about 4-5 times than that detected by GC. The addition of the catalyst inhibited the production of alcohols, acids, nitrogen and sugars, and promoted the formation of ketones, furan and hydrocarbons, but had little effect on esters and phenols. The Pt-Re-MCM-41 catalyst could increase the GC content of furan compounds. The GC content could reach 33.12% with 1.0%Pt-1.0%Re-MCM-41 as catalyst and the catalytic temperature was 450℃ and increased by 12.11 percentage point compared with that without catalyst. Low catalytic temperature (≤ 450℃) was favorable for the formation of 2 (5H) -furanone and 2-furan methanol, and high catalytic temperature (≥ 500℃) was beneficial for furfural, 2-methylfuran and 3-furfural formation. The activity of the 1.0%Pt-1.0%Re-MCM-41 catalyst was reduced after three times, and the activity was basically recovered after calcination. Among them, the furan compound GC antent reached 32.6%.