Effect of precursor synthesis on catalytic activity of Co3O4 in N2O decomposition.

Series of precursors was prepared by precipitation of cobalt nitrate in aqueous solutions using various precipitation agents (NH 3 ·H 2 O, NaOH, Na 2 CO 3 ) and reactions conditions (OH/Co molar ratio, aging time). Powder XRD showed different phase composition of the obtained precursors, in which β-Co(OH) 2 , Co II –Co III layered double hydroxide, and basic cobalt carbonate were identified. Only Co 3 O 4 spinel-like oxide was found in products after heating at 500 °C in air but different N 2 O conversions were observed over the examined oxide catalysts. Especially the catalysts obtained from β-Co(OH) 2 precursors showed high catalytic activity in N 2 O decomposition. The correlation between methods of preparation, phase composition of precursors, catalytic properties of the related oxide catalysts, and the role of the cobalt ions as catalytic active sites is discussed. [ABSTRACT FROM AUTHOR]