Rationales for the selection of the best precursor for potassium doping of cobalt spinel based deN(2)O catalyst

• Published in: Applied catalysis. B, Environmental Vol. 136-137; pp. 302 - 307
• Main Authors: Maniak, G, Stelmachowski, P, Kotarba, A, Sojka, Z, Rico-Perez, V, Bueno-Lopez, A
• Format: Journal Article
• Language: English
• Published: 05.06.2013
• Subjects: Catalysis; Catalysts; Cobalt; Potassium; Precursors; Spinel; Stability; Work functions
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2013.01.068

Cobalt spinel Co(3)O(4) catalysts promoted with different potassium precursors (K(2)CO(4), KNO(3), CH(3)COOK, KOH) were prepared and characterized by surface (XPS, work function, SEM) and structure (Raman, XRD, H(2)-TPR) sensitive techniques. The stability of potassium promoter was determined by means of Species Resolved-Thermal Alkali Desorption method (SR-TAD). The N(2)O decomposition mechanism on series of synthesized catalysts was studied by temperature programmed reaction and pulse experiments of iso-topically labeled (15)N(2)(18)O. The role of the octahedral cobalt ions as catalytic active sites was revealed. The most dispersed state of alkali promoter, obtained from K(2)CO(4) precursor, results in its highest stability and lowest work function, leading to the highest catalytic activity in N(2)O decomposition in the investigated K-Co(3)O(4) series. The beneficial effect of potassium is discussed in terms of the facile activation of N(2)O via dissociative electron transfer (N(2)O+e =N(2) + O(-1)) and promotion of the preferred fast suprafacial recombination of oxygen intermediates (revealed by the isotopic experiments).