高浓度过氧化氢分解用MnO_x/CeO_2-Al_2O_3整体催化剂

采用浸渍法制备了MnO x/CeO2-Al2O3整体催化剂,运用X射线衍射(XRD)和程序升温还原(TPR)方法对催化剂进行了表征,利用恒压排气量气法评价了催化剂分解过氧化氢反应的活性,并用单组元发动机热试考察了整体催化剂分解高浓度过氧化氢反应的稳定性。结果表明,CeO2通过形成表面活性氧和Mn-Ce-O固溶体,强化了MnO x与CeO2-Al2O3载体间的相互作用,将低价态Mn3+氧化到活泼的高价态Mn4+,增加了低温活性中心数,并促进了MnO x的分散,提高了催化剂的还原氧化能力。与MnO x/Al2O3催化剂相比,MnO x/CeO2-Al2O3整体催化剂对高浓度过氧化氢分解反应具有较高的活性和稳定性。

MnOx/CeO2-Al2O3 Monolith Catalyst for High Concentration Hydrogen Peroxide Decomposition

MnO_x/CeO₂-Al₂O₃ monolith catalysts were prepared by impregnation method. The catalysts were characterized by X-ray diffraction (XRD) and temperature-programmed reduction (TPR) methods, The H₂O₂ decomposition reaction activity was determined by oxygen-gasometry of the reaction kinetics in a constant pressure reactor. The stability of monolith catalysts for the decomposition of high concentration hydrogen peroxide was evaluated in a monopropellant thrust hot test system using 90% H₂O₂. The results show that CeO₂ can promote the interaction between MnO_x and CeO₂, the dispersion of Mn species, and the oxidation of low value Mn³⁺ to more active high value Mn⁴⁺, through the formation of surface active oxygen and Mn-Ce-O solid solution. The rise of more active Mn species of Mn⁴⁺ increases the number of low temperature active sites and the ability of reduction-oxidation of catalysts. MnO_x/CeO₂-Al₂O₃ monolith catalyst has a higher activity and stability for high concentration hydrogen peroxide decomposition reaction, compared to MnO_x/Al₂O₃ monolith catalyst.