화학공학소재연구정보센터
Applied Catalysis B: Environmental, Vol.185, 322-336, 2016
Synergetic effect of Pd addition on catalytic behavior of monolithic platinum-manganese-alumina catalysts for diesel vehicle emission control
The advanced diesel emission control catalyst Pt-Pd-MnOx-Al2O3 has been developed on the basis of the synergetic effect of Pt with Pd and manganese oxides observed in hydrocarbon and carbon monoxide oxidation reactions. This effect allows a decrease in the total loadings of Pt and Pd down to 0.52 g/L in the monolithic catalyst, providing high activity in low temperature oxidation of light hydrocarbons and high thermal stability. The catalytic activity of Pt-Pd-MnOx-Al2O3 monolithic catalysts in butane oxidation and DIESEL tests depends on the Pt and Pd precursors, their individual loadings and their ratio (Pt/Pd). For a selected Pt precursor at its content 0.17 g/L, the catalytic performance of Pt-Pd-MnOx-Al2O3 catalyst improves with an increase in Pd loading from 0 to 0.35 g/L and is nearly constant at a higher Pd loading (0.70 g/L). The most active monolithic Pt-Pd-MnOx-Al2O3 catalyst is prepared by using platinum-dinitrodiamine and palladium nitrate solutions as noble metal precursors. The catalytic activity in light hydrocarbon oxidation is shown to correlate with the RedOx properties of PdPt-MnOx-Al2O3 catalysts and the Pt-Pd particle size. The non-additive increase in the catalytic activity of bimetallic catalyst is suggested to connect with a formation of nanoscale PdO-PtOx particles on the surface of Mn3O4 and a modification of alumina structure by Mn3+ and PtPd clusters. (C) 2015 Elsevier B.V. All rights reserved.