Facile synthesis of Fe-modified manganese oxide with high content of oxygen vacancies for efficient airborne ozone destruction
Facile synthesis of Fe-modified manganese oxide with high content of oxygen vacancies for efficient airborne ozone destruction
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轻松合成具有高氧空位含量的铁改性氧化锰，可有效破坏空气中的臭氧
DOI：
10.1016/j.apcata.2017.08.013
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发表时间：
2017-09-25
影响因子：
5.5
通讯作者：
Zhang, Junying
中科院分区：
文献类型：
--
作者：
Jia, Jingbo;Yang, Wenjuan;Zhang, Junying
氧空位工程是提高纳米材料催化性能的有效途径。在这项工作中，一个高活性的铁改性锰氧化物（Fe-MnOx）的合成和用于空气中的臭氧分解。XPS、H-2-TPR分析表明，在MnO 2合成过程中加入Fe 3+，可使MnO 2的比表面积增大，氧空位含量显著增加，密度泛函理论计算的氧空位形成能降低约1.2 eV。在干燥条件下，Fe-MnOx催化剂上的臭氧转化率在24 h后仍保持在97%，而MnO 2催化剂上的臭氧转化率下降到85%。在湿度为60%的条件下，Fe-MnOx催化剂在反应6 h后臭氧转化率仍保持在73%，而纯MnO 2催化剂在100 ppm臭氧浓度和660 L g（-1）h（-1）的条件下，反应1 h后臭氧转化率降至50%.利用原位拉曼光谱研究了Fe-MnOx和MnO 2在臭氧分解过程中表面氧空位上形成的中间过氧化物物种（O-2（2-））。Fe-MnOx表面O-2（2-）的浓度和消耗速率均高于MnO 2表面，说明O-2（2-）是催化过程的关键物种。氧空位的含量和分散性被确定为主要负责的性能差异。这为设计新型纳米材料催化剂降解气态臭氧提供了一个很有前途的思路。
Oxygen vacancy engineering is an efficient strategy to improve the catalytic performance of nanomaterials. In this work, a highly active Fe-modified manganese oxide (Fe-MnOx) was synthesized and used for airborne ozone decomposition. The addition of Fe3+ during MnO2 synthesis led to higher specific surface area, greatly increased content of oxygen vacancies, evidenced by XPS, H-2-TPR analysis and lower oxygen vacancy formation energy (decreased by similar to 1.2 eV) based on the density functional theory calculations. The ozone conversion over Fe-MnOx kept 97% after 24 h reaction, while it over MnO2 slowed down to 85% under dry condition. Remarkably, under humid condition (RH = 60%), the ozone conversion over Fe-MnOx kept 73% after 6 h reaction, while ozone conversion over pure MnO2 decreased to 50% within 1 h under the conditions of 100 ppm inlet ozone concentration and weight space velocity of 660 L g(-1) h(-1). The intermediate peroxide species (O-2(2-)) formed on the surface oxygen vacancies of Fe-MnOx and MnO2 during ozone decomposition reaction were observed using in situ Raman spectroscopy. The concentration and depletion rate of O-2(2-) on the surface of Fe-MnOx was higher than that on MnO2, illustrating that O-2(2-) acted as the key species to boost the catalytic process. The content and dispersity of oxygen vacancies were identified to be mainly responsible for the performance difference. This provides a promising idea for designing novel nanomaterial catalyst for gaseous ozone decomposition.