摘要：采用水热合成法,通过加入不同种类的氧化剂合成不同晶型的二氧化锰催化剂,并利用X射线衍射、扫描电子显微镜、程序升温还原、氮气吸附-脱附和X射线光电子能谱等表征技术对所得到的样品进行表征分析。结果表明:以K₂S₂O₈作为氧化剂时,所得样品为α-MnO₂晶型,而以Na₂S₂O₈作为氧化剂时,所得样品为β-MnO₂晶型,这由K⁺的诱导效应所致;α-MnO₂比β-MnO₂具有更好的低温还原活性和更丰富的缺陷氧,在二甲醚催化燃烧中表现出比β-MnO₂更高的催化活性。

关键词：二氧化锰；水热合成；二甲醚；催化燃烧

Abstract：Manganese dioxide with different crystal phases were synthesized by different oxidants through a hydrothermal method. The synthesized MnO₂ samples were characterized by XRD, SEM, H₂-temperature programmed reduction, N₂ adsorption-disadsortion and XPS techniques. The results show that when K₂S₂O₈ or Na₂S₂O₈ are used as the oxidant, the products are α-MnO₂ and β-MnO₂ respectively, due to the inductive effect of K+. α-MnO₂ has better low-temperature activity and higher oxygen vacancy concentration than β-MnO₂, so α-MnO₂ exhibits better catalytic activity in dimethyl ether catalytic combustion.

Keywords: manganese dioxide；hydrothermal method；dimethyl ether；catalytic combustion