Oxygen effect in NO direct decomposition over K/Co-Mg-Mn-Al mixed oxide catalyst–Temperature programmed desorption study.

0543504 - ÚCHP 2022 RIV NL eng J - Journal Article
Pacultová, K. - Klegová, A. - Karásková, K. - Fridrichová, D. - Bílková, T. - Koštejn, Martin - Obalová, L.
Oxygen effect in NO direct decomposition over K/Co-Mg-Mn-Al mixed oxide catalyst–Temperature programmed desorption study.
Molecular Catalysis. Roč. 510, JUN 2021 (2021), č. článku 111695. ISSN 2468-8231. E-ISSN 2468-8231
R&D Projects: GA ČR(CZ) GA18-19519S
Institutional support: RVO:67985858
Keywords : mechanism * mixed oxide * oxygen effect * NO
OECD category: Chemical process engineering
Impact factor: 5.089, year: 2021
Method of publishing: Open access with time embargo

Co-Mg-Mn-Al mixed oxide with or without K was prepared and characterized by XPS, TPR H2, TPD NO, TPD O2 and TPD NO+O2. NO decomposition was performed over catalyst activated in different atmosphere (N2, He, O2). Presence of oxygen during activation changed the course of surface stabilization but did not affect NO conversion achieved at steady state. O2 desorbed as a reaction product does not affect the reaction rate for NO inlet concentration of 400 - 8000 ppm, but presence of O2 in inlet gas mixture (0.05 - 3 mol.%) has significant inhibiting effect. Transition metals in octahedral coordination represent sites for NO chemisorption, while potassium ensures NO oxidation to surface nitrites, which are indispensable reactive species. Oxygen desorption was the slowest reaction step, while N2 desorption was fast. Oxygen inhibition was ascribed to oxidation of NO* species on the octahedral Co3+ and Mn3+ to more stable surface nitrates making NO* species as limiting reactant.
Permanent Link: http://hdl.handle.net/11104/0320699