Abstract

The zirconia–alumina nanocatalyst was prepared using microwave combustion method, and the effects of alumina/zirconia ratio, fuel-to-oxidizer ratio, and calcination temperature on its structural and chemical performance were examined. Furthermore, the most suitable synthesized nanocatalyst was impregnated using different dosages of sulfate group to improve the activity of the sample for the esterification reaction. The results revealed that there was a significant improvement in the crystalline structure of alumina and zirconia for the samples having the alumina/zirconia ratio of 2. It was also noted that some amorphous structures were observed for low fuel dosages, while the activity of the sample was reduced with higher fuel consumption than the stoichiometric ratio, which can be attributed to the increase in the crystallite size and formation of different alumina phases. Based on calcination results, non-considerable changes were observed in the morphology and activity of the catalyst. It can be concluded that the solution combustion method is suitable for nanocatalyst preparation without any requirement of further thermal treatment. In addition, the activity of the sample was enhanced by impregnation with H₂SO₄ where the conversion of 91.6% was achieved. The catalyst showed high reusability at least for seven times as well as high stability of zirconia–alumina as a support.

Graphical abstract

中文翻译：

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微波辐射在燃烧法酯化反应制备硫酸化ZrO 2 -Al 2 O 3纳米复合材料中的应用：工艺条件评价

摘要

采用微波燃烧法制备了氧化锆-氧化铝纳米催化剂，并考察了氧化铝/氧化锆比，燃料-氧化剂比和煅烧温度对其结构和化学性能的影响。此外，使用不同剂量的硫酸根浸渍了最合适的合成纳米催化剂，以提高样品进行酯化反应的活性。结果表明，氧化铝/氧化锆比为2的样品的氧化铝和氧化锆的晶体结构有显着改善。还注意到在低燃料剂量下观察到一些无定形结构，而样品的活性比化学计量比更高的油耗降低了油耗，这可以归因于微晶尺寸的增加和不同氧化铝相的形成。基于煅烧结果，在催化剂的形态和活性方面观察到非常小的变化。可以得出结论，溶液燃烧法适用于纳米催化剂的制备，不需要任何进一步的热处理。另外，通过用H浸渍提高了样品的活性。₂ SO ₄，其转化率为91.6％。该催化剂显示出至少七次的高可重复使用性，以及作为载体的氧化锆-氧化铝的高稳定性。

图形概要