Kinetic analysis of N2O decomposition over calcined hydrotalcites

Kinetics of N2O decomposition over catalyst prepared by calcination of Co–Mn hydrotalcite was examined in integral fixed-bed reactor (V˙/w=12–96 l gcat−1 h−1) at various N2O and O2 initial partial pressure at temperature range of 330–450 °C. Kinetic data were evaluated by linear and non-linear regression method, 15 kinetic expressions were tested. Based on the obtained results a redox model of N2O decomposition was proposed. At low pressures of O2, adsorbed oxygen is formed by the N2O decomposition; the N2O chemisorption is considered as the rate-determining step. On the contrary, at high O2 pressure it could be assumed that adsorbed oxygen species appear as a result of O2 adsorption and the Eley–Rideal mechanism is the rate determining. N2O decomposition is well described by the 1st rate law at N2O and O2 concentrations typical for waste gases.