Role of Structural Defects in MnOx Promoted by Ag Doping in the Catalytic Combustion of Volatile Organic Compounds and Ambient Decomposition of O3
Role of Structural Defects in MnOx Promoted by Ag Doping in the Catalytic Combustion of Volatile Organic Compounds and Ambient Decomposition of O3
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Ag掺杂促进MnOx结构缺陷在挥发性有机化合物催化燃烧和O3常温分解中的作用
DOI：
10.1021/acs.est.9b01822
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发表时间：
2019-09-17
影响因子：
11.4
通讯作者：
He, Hong
中科院分区：
文献类型：
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作者：
Deng, Hua;Kang, Shunyu;He, Hong
锰氧化物是催化氧化挥发性有机化合物（VOCs）或环境分解O-3的重要候选者。在这里，我们比较了不同的制备方法，以创建富缺陷的Ag-MnOx纳米复合材料，在VOC燃烧和臭氧分解方面表现出显著的多功能活性。Ag+离子通过水热取代原来的K+离子，在Ag- mnox - h的微孔道中分散良好；该催化剂的苯燃烧效率(T-90% = 216℃，空速为90000 mL h（-1) g(-1)）与典型的贵金属催化剂相当。此外，在相对湿度为60%的条件下，Ag-MnOx-H催化剂(空速= 840 000 mL h（-1) g(-1)）上臭氧的分解率在90%以上，表明该催化剂在实际应用中是一种很有前景的臭氧消除材料。局部结构结果表明，通过水热法掺入银有利于MnOx基体中非化学计量缺陷的形成。大量与O空位相关的活性氧在VOC燃烧中起关键作用；此外，由O缺陷产生的氧空位也是O-3消减的关键。本研究为挥发性有机化合物燃烧和环境O-3分解提供了多功能催化剂，有助于合理设计各种条件下的MnOx催化剂。
Manganese oxides are prominent candidates for the catalytic oxidation of volatile organic compounds (VOCs) or ambient decomposition of O-3 individually. Here, we compared various preparation methods to create a defect-enriched Ag-MnOx nanocomposite that exhibits a remarkably multifunctional activity in VOC combustion and ozone decomposition. Ag+ ions were well-dispersed in the microtunnels of Ag-MnOx-H via hydrothermal replacement of the original K+ ions; this catalyst's benzene combustion efficiency (T-90% = 216 degrees C at a space velocity of 90 000 mL h(-1) g(-1)) was comparable to that of typical noble metal catalysts. Moreover, the decomposition of ozone over the Ag-MnOx-H catalyst (space velocity = 840 000 mL h(-1) g(-1)) under a relative humidity of 60% was above 90%, indicating that it is a promising material for ozone elimination in practical application. The local structure results indicated that silver incorporation via the hydrothermal method facilitates the formation of nonstoichiometric defects in the MnOx matrix. The large number of active oxygen species related to O vacancies appeared to play critical roles in VOC combustion; moreover, the oxygen vacancies originating from O defects were also critical in O-3 abatement. This work provides multifunctional catalysts for VOC combustion and ambient O-3 decomposition and may assist with the rational design of MnOx catalysts for application in various conditions.