化工学报 ›› 2023, Vol. 74 ›› Issue (7): 2908-2918.DOI: 10.11949/0438-1157.20230420

• 催化、动力学与反应器 • 上一篇    下一篇

Ru/α-MnO2催化剂形貌对NH3-SCO反应性能的影响

李盼(), 马俊洋, 陈志豪, 王丽(), 郭耘   

  1. 华东理工大学化学与分子工程学院工业催化研究所,上海 200237
  • 收稿日期:2023-04-26 修回日期:2023-06-26 出版日期:2023-07-05 发布日期:2023-08-31
  • 通讯作者: 王丽
  • 作者简介:李盼(1998—),女,硕士研究生,lipan0405@163.com
  • 基金资助:
    国家自然科学基金项目(21976057)

Effect of the morphology of Ru/α-MnO2 on NH3-SCO performance

Pan LI(), Junyang MA, Zhihao CHEN, Li WANG(), Yun GUO   

  1. Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
  • Received:2023-04-26 Revised:2023-06-26 Online:2023-07-05 Published:2023-08-31
  • Contact: Li WANG

摘要:

以具有不同形貌的线状(w)、管状(t)和棒状(r)的α-MnO2为载体制备了Ru/α-MnO2催化剂,考察了载体形貌对于氨选择性催化氧化(NH3-SCO)反应性能的影响,并利用多种手段表征了催化剂的物化性质、氧化还原性能和酸性。α-MnO2形貌影响所暴露的晶面;线状、纳米棒和管状α-MnO2分别暴露(110)、(310)和(200)晶面。Ru的引入提高了催化剂的耐水性能,其中管状Ru/α-MnO2在水汽条件下NH3转化率为86%,N2的选择性为98%。Ru的引入对反应性能的影响与其对α-MnO2表面酸性、氧化还原性能的影响密切相关。Ru降低了α-MnO2-w表面酸量导致其活性下降;Ru对于α-MnO2-r氧化性能的提高弥补了其导致的表面酸量的降低;而Ru对α-MnO2-t氧化性和酸量的同时促进是Ru/α-MnO2-t反应性能提升的主要原因。

关键词: 催化剂, 载体, 氧化, 氨选择性催化氧化, α-MnO2形貌, 酸性, 氧化还原性

Abstract:

α-MnO2 with different morphology, such as wire (w), tube (t) and rod (r) were synthesized as supports to prepare Ru/α-MnO2, and the effects of support morphology on the ammonia selective catalytic oxidation (NH3-SCO) were investigated. Meanwhile, the physical and chemical properties, redox properties and acidity of the catalysts were characterized by various methods. The exposed facet was closely related to the morphology of α-MnO2, for (110), (310) and (200) crystal planes were observed on the wire-, tube-, and rod-α-MnO2, respectively. The introduction of Ru improves the water resistance of the catalyst, and the tubular Ru/α-MnO2 has a NH3 conversion rate of 86% and a N2 selectivity of 98% under water vapor conditions. The effects of Ru on NH3-SCO activity performance was closely related to its effect on the surface acidity and redox property of α-MnO2. The addition of Ru reduced the surface acid amount of α-MnO2-w and thus lowered its activity, while the improved reducibility of Ru to α-MnO2-r compensated for the decreasing in the surface acid amount. However, for Ru/α-MnO2-t, the simultaneous increase in reducibility and surface acid amount by the presence of Ru was the main reason for the enhancement in NH3-SCO activity.

Key words: catalyst, support, oxidation, NH3 selective catalytic oxidation, morphologies of α-MnO2, acidity, redox

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