Influence of Ceria and Lanthana Promoters on the Kinetics of NO and N2O Reduction by CO over Alumina-Supported Palladium and Rhodium

Time Decay of the Activity of the Reduction Reaction of NO by CO on a Pd/Al2O3 Catalyst

“…5 linearized to obtain parameters m and n, considering the initial and final steady state values in both cases. The negative order with respect to CO and positive for NO, agrees in the steady state case with those reported by Holles et al [8,9] and with those of Reiner et al [7] for the same system. On the other hand, the increase of the negative parameter value for CO and the decrease of the positive parameter with respect to NO between the initial states and the steady state, reflect the system's deactivation through a decrease of R CO 2 according to Eq.…”

“…1d it is seen that the Arrhenius straight line is fulfilled with a high correlation in the temperature interval studied, getting a high apparent activation energy equal to 12.8 (kcal/mol). It is interesting to note that for the same system a wide spectrum of values has been reported for the apparent activation energy [6,7,24,25], as pointed out by Holles et al [9], who give values that vary between 10.2 and 14.3 (kcal/mol) for various catalyst loads. These activation energies are of the same order as those obtained in our experiments.…”

“…In this paper we are interested in studying the CO-NO reaction over palladium supported on alúmina, considering the dispersed information reported for this system, such as that of Holles et al [9] that we will comment below. Our main interest, however, which is probably related to the above, is the deactivation over time that this system undergoes during the process of the reaction, making it difficult to achieve the steady state.…”

“…For example, Reiner et al [6,7] and Holles et al [8,9] have published data obtained from a conventional flow reactor, while Prevot et al [10,11], Nakao et al [12] and Thirumoorthy et al [13] used molecular beam techniques.…”

Catalysis for NOx abatement

“…A bi-functional mechanism based on Pd 2+ being the adsorbent of NO and CO and the oxide ion vacancies for NO dissociative chemisorption was proposed and this model fits the experimental data well. The ionic catalysts not only have the higher TOF at lower temperature but also higher selectivity of N 2 compared to the other catalysts reported in the literature [83][84][85].…”