Cu-Mg-Fe-O-(Ce) Complex Oxides as Catalysts of Selective Catalytic Oxidation of Ammonia to Dinitrogen (NH3-SCO)

Catalysts

卷:10

Sylwia Górecka¹  Kateřina Pacultová¹  Aneta Smýkalová¹  Kamil Górecki¹  Lucie Obalová¹  Katarzyna Pamin² 

[1] Institute of Environmental Technology, VŠB – Technical University of Ostrava, 17. listopadu 15/2172, 708 00 Ostrava, Czech Republic;

[2] Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Niezapominajek 8, 30-239 Kraków, Poland;

关键词: selective catalytic oxidation;    ammonia;    nh₃-sco;    mixed metal oxides;    mgfe₂o₄ type spinel oxides;    cu-fe-ce based oxides;    cu-ce redox couples;    cu-fe redox couples;   

DOI  :  10.3390/catal10020153

来源: DOAJ

【 摘 要 】

Multicomponent oxide systems 800-Cu-Mg-Fe-O and 800-Cu-Mg-Fe-O-Ce were tested as catalysts of selective catalytic oxidation of ammonia to dinitrogen (NH₃-SCO) process. Materials were obtained by calcination of hydrotalcite-like compounds at temperature 800 °C. Some catalysts were doped with cerium by the wet impregnation method. Not only simple oxides, but also complex spinel-like phases were formed during calcination. The influence of chemical composition, especially the occurrence of spinel phases, copper loading and impregnation by cerium, were investigated. Materials were characterized by several techniques: X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), low-temperature nitrogen adsorption (BET), cyclic voltammetry (CV), temperature programmed reduction (H₂-TPR), UV-vis diffuse reflectance spectroscopy and scanning electron microscopy (SEM). Examined oxides were found to be active as catalysts of selective catalytic oxidation of ammonia with high selectivity to N₂ at temperatures above 300 °C. Catalysts with low copper amounts (up to 12 wt %) impregnated by Ce were slightly more active at lower temperatures (up to 350 °C) than non-impregnated samples. However, when an optimal amount of copper (12 wt %) was used, the presence of cerium did not affect catalytic properties. Copper overloading caused a rearrangement of present phases accompanied by the steep changes in reducibility, specific surface area, direct band gap, crystallinity, dispersion of CuO active phase and Cu²⁺ accessibility leading to the decrease in catalytic activity.

【 授权许可】

Unknown