The number of active oxygen species (Os) on the surface of Cr2O3 catalysts was determined by using the rectangular pulse technique coupled with the reaction of NH3 with a preoxidized catalyst, i.e., 2 NH3 + 3Os → N2 + 3H2O and 2NH3 + 4Os → N2O + 3H2O. The observed number of active oxygen species was found not to change with experimental variables such as temperature, carrier gas flow rate, weight of catalyst, and pulse width. The area occupied by a site, which is defined as the BET surface area divided by the number of active oxygen species, was almost constant for three kinds of Cr2O3 catalysts prepared by different methods, and it was close to literature data.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry