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摘要: 用微型催化反应装置结合吡啶吸附红外光谱、热重、氢化学吸附和程序升温等还原手段,研究了添加碱土金属离子助剂对负载型PtSn/γ-Al2O3催化剂长链烷烃(C10~13)脱氢反应性能的影响。结果表明,碱土金属助剂的引入可以降低催化剂积炭量、提高催化剂铂金属表面裸露度,从而提高催化剂脱氢反应稳定性。但强碱性的碱土金属助剂如Ba2+的引入增强了锡与载体之间的相互作用,减弱了锡与铂之间的相互作用, 导致反应后催化剂铂金属表面裸露度下降,故PtSnBa/γ-Al2O3催化剂脱氢活性较低。Abstract: The effect of alkalineearth promoters on the catalytic properties of supported PtSn/γ-Al2O3 catalysts for longchain paraffin (C10~13) dehydrogenation has been studied by using infrared spectroscopy of adsorbed pyridine (Py-IR), thermalgravimetry (TG), H2 chemisorption and temperatureprogrammed reduction (TPR) combined with microreactor tests. The results show that addition of alkalineearth metal (Mg, Ca, Sr, Ba) to PtSn/γ-Al2O3 can improve its catalytic stability for paraffin dehydrogenation by decreasing the amount of coke formed on the catalysts and increasing the fraction of bare metallic Pt surface after carbon deposition.However, coaddition of alkalineearth metal with higher basicity, e.g. Ba2+, results in stronger interaction between Sn and support, leading to weaker interaction between Pt and Sn and decrease of bare fraction of Pt after carbon deposition. As a result, the PtSnBa/γ-Al2O3 catalyst shows a lower catalytic activity for longchain paraffin dehydrogenation.
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Key words:
- platinumtin catalysts /
- alkalineearth metal ions /
- promoter /
- longchain paraffin /
- dehydrogenation
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