Catalysis Today, Vol.192, No.1, 123-129, 2012
New insights into the development of Bronsted acidity of niobic acid
The development of Bronsted acidity and the relationship between acidity, catalytic performance and structure of niobium oxide were investigated for a series of samples prepared by calcination of niobic acid at temperatures between 423 and 823 K. All solids were active for propan-2-ol dehydration. The Bronsted acidity was monitored by adsorption of lutidine and CO followed by FT-IR. Low temperature CO adsorption measurements showed that all solids exhibit essentially the same medium Bronsted acid strength. A direct relationship between the abundance of Bronsted acid sites monitored by lutidine adsorption followed by desorption at 523 K and propan-2-ol dehydration activity was observed. (c) 2012 Elsevier B.V. All rights reserved.
Keywords:Niobium oxide;Niobic acid;Bronsted acidity;Isopropanol dehydration;Correlation acidity-activity