Effect of Macropore Formation in Pt Catalyst Supports on the Oxidation Activity for Diesel Fuel Mist

Abstract

The effect of macropore formation in catalyst supports on the oxidation activity for diesel fuel mist was examined with the goal of improving catalyst efficiency. To investigate the effect on a laboratory scale using granular samples, we designed a reaction system that supplied fuel mist to the catalyst bed directly by an air atomizing nozzle. The catalytic activity was found to be improved by macropore formation in the support. This effect was also demonstrated for a washcoated catalyst on a honeycomb with diesel engine exhaust. These results suggest that the macropore diffusion channels are secure even if fuel mist attaches to the support surface, and the reactant gas can diffuse to the interior of the support and reach the active sites. Macropore formation prevented the blockage of pores of the support surface and thus the active sites of the catalyst.

Improvement of Silica–alumina Supports for Diesel Oxidation Catalysts through Control of Both Composition and Pore Structure

“…16. Here it can be seen that the activity obtained with the hybrid support was higher than that obtained when using the support without macro- 24) . Copyright 2012 American Chemical Society.…”

“…Taken together, these results suggest that a similar promotional effect associated with reduced basicity appears in the SiO2 _ Al2O3 catalyst. Res., 51, 719 (2012) 24) . Copyright 2012 American Chemical Society.)…”

“…Copyright 2014 American Chemical Society.) Res., 51, 719 (2012) 24) . Copyright 2012 American Chemical Society.)…”

“…We therefore anticipate that the catalytic activity of the above-mentioned 3.9 wt% SiO2 _ Al2O3 sample could be further improved by increasing the mesopore size to 10 nm. 24) 3. 2.…”

Mapping the Pore Architecture of Structured Catalyst Monoliths from Nanometer to Centimeter Scale with Electron and X-ray Tomographies

“…In most cases knowledge transfer to real world applications is limited, since the native catalyst form is a washcoated monolith and not a sieved powder or compressed pellet. Fundamental knowledge of the pore system in hierarchicallystructured catalysts is also important to understand reactant diffusion, accessibility of active sites and structural integrity [12][13][14] . Porosity is often examined using methods such as Hg porosimetry or gas adsorption isotherms, which can be regarded as one-dimensional bulk analyses.…”