Mokhnachuk O. The influence of carrier nature and modifying additives on structural and functional characteristics of Pd/Al2O3 monolithic catalysts of nitrogen oxide reduction by methane.

It was established that parameters of porous structure of Al2O3 as secondary carrier of the structured catalysts of high-temperature processes depend on the nature of precursors and conditions of synthesis. Introduction of La2O3 either individually or together with СеО2 raises thermal stability of porous structure of alumina that is caused by formation of a solid solution of lanthanum oxide in Al2O3. The optimal composition of the catalyst was established as (0,5%Pd/2%Al2O3+5%La2O3/cordierite). It was shown that extreme dependence of activity of the catalyst on the alumina contents is caused by influence of increase in acidity of the secondary carrier on palladium activity owing to difficulty of transition of the palladium in more active reduced form and infringements of balance of rates of stages of activation of reagents. The effect of thermal activation of the Pd/La2O3/Al2O3 catalyst was found and explained by stabilization of a palladium in (+1) oxidation state. Comparative tests for model installations have shown that the catalyst developed from the point of view of activity is not inferior, and from the selectivity exceeds the granulated industrial catalyst - APC-2.