Macroporous SmMn₂O₅ mullite for NO_x-assisted soot combustion

Abstract

A series of mullite SmMn2O5 oxides were prepared by citric acid (CA), hydrothermal (HT) and co-precipitation (CP) and combustion of ethylene glycol and methanol solutions (EG&M) methods, and tested for NOx-assisted soot combustion.

Highly dispersed Pd on macroporous SmMn2O5 mullite for low temperature oxidation of CO and C3H8

“…The rst two consecutive peaks at 381 C and 458 C result from the consumption of adsorbed oxygen and reduction of Mn 4+ to Mn 3+ . 24,27,28 Aer the deposition of Pd, the release of the surface oxygen species for EG&M sample is greatly promoted as evidenced by the decline of reduction peak to 138 C. In addition, the reduction temperature of Mn 4+ and Mn 3+ decreases to 295 C and 407 C, suggesting the facile reduction of adsorbed oxygen and Mn ion by loading palladium species. The reason for the decrease of reduction temperatures is attributed to the hydrogen spillover effect, because hydrogen is easily dissociated at the reduced Pd surface and spilled to the SMO support.…”

“…[57][58][59] In addition, the enhanced activity of oxygen species (certied by CO + O 2 pulse hereaer) contributes as well. 28,37 As the Pd dispersion is higher for the Pd/SMO-EG&M compared with other samples, its surface Pd site was highly exposed and could be reduced easier. The lower temperature suggests higher reducibility of the Pd/SMO-EG&M in the whole range, suggesting that the reduction of mobile oxygen and surface adsorbed oxygen species is more facile.…”

“…3c illustrates the Mn 2p XPS spectrum with Mn 2p 3/2 at 641.9 eV and Mn 2p 1/2 at 652.9 eV, respectively. Herein, the lower asymmetrical Mn 2p 3/2 peak can be tted into two [26][27][28]48 For the pristine EG&M sample, the BE values for lattice oxygen and surface adsorbed oxygen species are 529.1 eV and 531.2 eV, respectively. However, the values shi to 529.7 eV and 531.4 eV aer Pd addition, and a similar behavior is found for the CP sample.…”

Three-dimensionally ordered macroporous SnO2-based solid solution catalysts for effective soot oxidation

“…For 3DOM-Mn1Sn9, two XPS Mn 3p3/2 peaks at 641.6 and 645.4 eV are observed (Fig. 9(C)), which are assigned to Mn 3+ and Mn 4+ [49,50], respectively. The Mn 3p1/2 peak at 653.7 eV is also characteristic of Mn 3+ .…”

Fabrication of ultrafine Pd nanoparticles on 3D ordered macroporous TiO2 for enhanced catalytic activity during diesel soot combustion

“…One efficient exhaust gas treatment system is the continuously regenerating particulate trap (CRT) technique, which is based on the use of highly active catalytic materials [3,4]. Over several decades of development, several materials exhibiting high catalytic activity for soot combustion have been identified, including noble metals, transition metal oxides, alkaline metal oxides, perovskite-like oxides and ceria-based oxides [5][6][7][8][9]. However, it remains challenging to fabricate highly active catalytic systems for soot combustion, and developing high-performance catalysts requires an understanding of the properties that affect catalytic activity.…”