Soot Combustion over Niobium-Doped Cryptomelane (K-OMS-2) Nanorods—Redox State of Manganese and the Lattice Strain Control the Catalysts Performance

Catalysts

Piotr Legutko¹  Andrzej Adamski¹  Zbigniew Sojka¹  Monika Fedyna¹  Janusz Janas¹  Joanna Gryboś¹  Andrzej Kotarba¹  Xuehua Yu²  Zhen Zhao²  Jakub Szlachetko³  Anna Wach³ 

[1] Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387 Krakow, Poland;Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, China;Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego, 152, 31-342 Krakow, Poland;

关键词: soot;    oxidation;    cryptomelane;    combustion;    niobium dopant;   

DOI  :  10.3390/catal10121390

来源: DOAJ

【 摘 要 】

A series of Nb-doped (0–23 wt%) cryptomelane catalyst (Nb-K-OMS-2) was synthesized and thoroughly characterized by XRD, TEM/EDX, XRF, XPS, XAS, UV-Vis, and Raman techniques corroborated by the work function measurements. The obtained catalysts were tested for soot oxidation (Printex U) in model tight and loose contact modes. It was shown that the catalytic properties of the Nb-K-OMS-2 are controlled by the amount of Nb dopant in a strongly non-monotonous way. The introduction of niobium gives rise to the strain in the cryptomelane lattice, accompanied by significant Mn⁺³/Mn⁺⁴ ratio variations and concomitant work function changes. The isotopic exchange experiments revealed that the catalytic activity of the Nb-OMS-2 catalysts in soot combustion proceeds via the pathways, where both the activated suprafacial ¹⁸O and the surface ¹⁶O^2– species participate together in the reaction. The niobium doping level controls the non-monotonous changes of the catalyst work function and the lattice strain, and variations of these parameters correlate well with the observed deSoot activity. To our best knowledge, the role of the lattice strain of the cryptomelane catalysts was documented for the first time in this study.

【 授权许可】

Unknown