The NONH3 reaction on vanadium oxide catalyst under the dilute gas condition was markedly accelerated by the addition of O2. The oxygen species responsible for the acceleration of the reaction has been found to be the V3+O species on the catalyst; the rate of the NONH3 reaction at a given O2 concentration was in proportion to the amount of the V3+O species in the catalyst. On the basis of the results of the kinetics of the reaction in the presence of O2, the adsorptions of NH3 and NO, and the reaction of adsorbed NH3 and gaseous NO, the mechanism of the NONH3 reaction on vanadium oxide catalyst under the dilute gas condition has been established as follows: NH3 is strongly adsorbed adjacent to V3+O as NH4 + (ad), whereas, NO is hardly adsorbed on the catalyst. Then, agaseous NO reacts with the adsorbed NH3, i.e., NH4 + (ad), to form N2, H2O, and VOH. The VOH species is reoxidized to V3+O by either gaseous O2 or bulk V3+O species. The rate of the NONH3 reaction in the presence of O2 has been proven to agree with that calculated by using the transition state theory together with the above-mentioned mechanism.
ASJC Scopus subject areas
- Process Chemistry and Technology