臭氧作为一种强氧化性物质，被广泛应用于室内空气净化、饮用水净化、污水污泥处理以及食品加工处理等行业，但臭氧同时也是一种主要大气污染物，在很低浓度下就会对人体健康产生威胁，亟需研究开发高抗水性能、高去除效率的臭氧常温分解催化剂。本论文以干燥条件下活性最佳的α-MnO2和γ-MnO2为研究对象，通过“改变合成方法+酸溶解二次处理”进行改性修饰，研究不同改性方法对MnO2形貌结构、表面性质和催化活性等的影响。主要研究成果如下：（1）发现α-MnO2固相合成方法与传统水热合成法相比，固相法工艺条件更温和简单，可以在维持α-MnO2较大比表面积（131.98 m2·g-1）的同时获得更小的平均孔径（8.10 nm），促进臭氧传质，同时在一定程度上提高α-MnO2的氧化还原能力，显著增加表面氧空位和酸性位含量，强化臭氧催化分解。活性测试表明，固相法α-MnO2在4小时内的臭氧转化率一直稳定在93%以上，高于水热法α-MnO2（约85%），活性和稳定性都更为优秀。但固相合成的α-MnO2抗水性能相对较差，需要进一步寻找表面改性方法。（2）研究了硝酸和醋酸处理对固相法α-MnO2的改性作用，发现两种酸处理都可以强化抗水和抗NOx能力，但只有适当浓度的硝酸处理可以带来更大的比表面积（192.98 m2·g-1）、更多的表面氧空位和更丰富的表面酸性位，提高固相法α-MnO2的活性与稳定性（4小时内臭氧转化率提高到97%以上）。基于催化剂表面性质特点，提出了一种表面氧空位-酸性位协同催化臭氧分解的反应机理，解释了Br?nsted酸性位强化臭氧催化分解的作用，并通过DFT理论计算进行了验证。（3）采用硝酸选择性溶解方法探究了γ-MnO2原位改性合成方案的可行性，发现硝酸会通过选择性溶解La原子诱导结构坍缩和重整，在合成时就显著增大γ-MnO2的比表面积（278.57 m2·g-1），引入大量晶格缺陷和氧空位，同时硝酸处理改性还会弱化催化剂表面对H2O的吸附，显著提高抗水能力，多方面综合增强γ-MnO2的催化活性与稳定性（12小时内臭氧转化率提高到90%以上），为将来的催化剂设计提供了一种新思路。

Ozone is widely used in various industries such as indoor air purification, drinking water purification, sewage sludge treatment, and food processing for its strong oxidizing properties. However, ozone, also as a major atmospheric pollutant, can pose a threat to human at very low concentrations. Therefore, it is of great importance to develop catalysts with strong water resistance and high removal efficiency for ozone decomposition at room temperature. In this work, the method of changing synthesis route and acid treatment was adopted to modify α-MnO2 and γ-MnO2, which possessed the best performance under dry conditions. The effects of different modification methods on the morphology, structure, surface properties and catalytic ozone decomposition activity of manganese dioxides were emphatically studied. The main conclusions are as follows:(1) The advantages and disadvantages of solid phase synthesis of α-MnO2 were analyzed. Compared with the traditional hydrothermal method, the technological conditions of solid phase synthesis were much milder and simpler. The α-MnO2 synthesized by solid phase method could obtain a smaller average pore size (8.10 nm) while maintaining a relatively larger specific surface area (131.98 m2·g-1), which promoted the mass transfer of ozone. At the same time, the solid phase method also slightly improved the oxidation-reduction capacity, significantly increased the content of oxygen vacancies and acid sites, and strengthened the catalytic ozone decomposition activity of α-MnO2. The acticity tests showed that, the ozone conversion of α-MnO2 synthesized by solid phase method maintained more than 93% within 4 hours, which was higher than that of α-MnO2 from hydrothermal method (~85%). However, the water resistance of α-MnO2 from solid phase synthesis was relatively poorer, making it necessary to find further modification methods.(2) The modification effects of nitric acid and acetic acid treatment on α-MnO2 synthesized by solid phase method were investaged. It was found that both acid treatments could strengthen the water and NOx tolerance of α-MnO2, but only proper concentration of nitric acid treatment would bring greater specific surface area (192.98 m2·g-1), more oxygen vacancies and richer acid sites, improving the activity and stability of α-MnO2 from solid phase synthesis (ozone conversion within 4 hours increased to more than 97%). Based on the surface properties of these catalysts, a mechanism in which oxygen vavancies and acid sites synergistically contributed to ozone decomposition was proposed and verified by DFT calculations, which further explained the role of Br?nsted acid sites in enhancing the catalytic ozone decomposition performance.(3) The feasibility of the in-situ modification and synthesis scheme of γ-MnO2 was explored. It was found that nitric acid could induce structural collapse and reforming by selectively dissolving La atoms, which significantly increased the specific surface area (278.57 m2·g-1) of γ-MnO2 and introduced a large number of lattice defects and oxygen vacancies during synthesis. At the same time, the modification of nitric acid treatment had also been completed, weakening the adsorption affinity between H2O and catalyst surface, and significantly improving the water resistance of γ-MnO2. This method of selective dissolution comprehensively enhanced the catalytic activity and stability of γ-MnO2 (ozone conversion within 12 hours increased to more than 90%), providing a new synthesis and modification idea for future catalysts design.