Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (5): 722-732.DOI: 10.1016/S1872-2067(18)63269-9

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Three-dimensional ordered macroporous perovskite-type La1-xKxNiO3 catalysts with enhanced catalytic activity for soot combustion: the Effect of K-substitution

Xuelei Mei, Jing Xiong, Yuechang Wei, Chujun Wang, Qiangqiang Wu, Zhen Zhao, Jian Liu   

  1. State Key Laboratory of Heavy Oil Processing, College of Science, China University of Petroleum-Beijing, Beijing 102249, China
  • Received:2018-10-23 Revised:2018-11-21 Online:2019-05-18 Published:2019-03-30
  • Contact: 10.1016/S1872-2067(18)63269-9
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21673142), National Engineering Laboratory for Mobile Source Emission Control Technology (NELMS2017A05), PetroChina Innovation Foundation (2018D-5007-0505), and Science Foundation of China University of Petroleum, Beijing (242017QNXZ02, 2462018BJC005).

Abstract:

Three-dimensional ordered macroporous (3DOM) La1-xKxNiO3 perovskite-type catalysts were successfully prepared by a colloidal crystal template method and characterized by scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray scattering elemental mapping, X-ray diffraction, Raman and X-ray photoelectron spectroscopy, and temperature-programmed reduction of H2. Further, their catalytic activity in soot combustion was determined by temperature-programmed oxidation reaction. K substitution into the LaNiO3 lattice led to remarkably improved catalytic activity of this catalyst in soot combustion. Amongst various catalysts, La0.95K0.05NiO3 exhibited the highest activity in soot combustion (with its T50 and SCO2 values being 338℃ and 98.2%, respectively), which is comparable to the catalytic activities of Pt-based catalysts under the condition of poor contact between the soot and the catalyst. K-substitution improves the valence state of Ni and increases the number of oxygen vacancies, thereby leading to increased density of surface-active oxygen species. The active oxygen species play a vital role in catalyzing the elimination of soot. The perovskite-type La1-xKxNiO3 nanocatalysts with 3DOM structure without noble metals have potential for practical applications in the catalytic combustion of diesel soot particles.

Key words: Three-dimensional ordered, macroporous material, LaNiO3 Potassium, Perovskite, Soot combustion