| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 87 === The goals of this research were to investigate the effects of catalyst preparation and pretreatment conditions on the Pd-Pt bimetallic interactions thereby developing a high sulfur-resistance catalyst for the reduction of aromatics in diesel fuel. The test reactions were conducted with the feed of 500 ppm sulfur containing tetralin. The reaction were carried out in a continuous fixed bed reaction system at 480psig, 300 oC, WHSV= 4h-1, and H2/Oil=4.3. CO chemisorption, fast Fourier transform infrared (FFT-IR) spectroscopy, extended X-ray absorption fine structure (EXAFS)spectroscopy, and temperature programmed reduction (TPR) were used to characterize both fresh and used catalysts. With the complementary experiments, the following conclusions were obtained:
1. The main reason of catalytic deactivation is caused by the absorption H2S on Pt clusters, the formation of PtS and the agglomeration of Pt clusters induced from the adsorption of H2S.
2. Based on FFT-IR, EXAFS, TPR and catalytic performance results, we confirmed that the formation of bimetallic interactions catalyst and the change of electronic properties induced from the interactions inhibit the adsorption of H2S and thus decreases the agglomeration of metal clusters.
3. Only the catalysts having co-catalytic reduction properties presents bimetallic interactions and the existence of co-catalytic reduction is strongly dependent on the preparation conditions and the pretreatment conditions.
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