Investigation of Platinum and Cerium From Use of a FBC

Document Number: 2006-01-1517

Date Published: April 2006

Author(s):
Martin Merrill Shafer - Univ. of Wisconsin Madison
James J. Schauer - Univ. of Wisconsin Madison
Walter Copan - Clean Diesel Technologies Inc.
Jeremy D. Peter-Hoblyn - Clean Diesel Technologies Inc.
James Valentine - Clean Diesel Technologies Inc.
Barry Sprague - Clean Diesel Technologies Inc.

Abstract:
Fuel-borne catalysts (FBC) have demonstrated efficacy as an important strategy for integrated diesel emission control. The research summarized herein provides new methodologies for the characterization of engine-out speciated emissions. These analytical tools provide new insights on the mode of action and chemical forms of metal emissions arising from use of a platinum- and cerium-based commercial FBC, both with and without a catalyzed diesel particulate filter.

Characterization efforts addressed metal solubility (water, methanol and dichloromethane) and particle size and charge of the target species in the water and solvent extracts. Platinum and cerium species were quantified using state-of-the-art, high-resolution plasma mass spectrometry. Liquid-chromatography-triple quad mass spectrometry techniques were developed to quantify potential parent Pt-FBC in the PM extracts. Speciation was examined for emissions from cold and warm engine cycles collected from an engine dynamometer.

Water-soluble platinum (6-hour extractions, 0.45 \gmm filtered) species represented a small fraction (2.8 \mP 1.5%) of total aerosol-associated platinum. A large fraction of the water-soluble platinum (44 \mP 8%) was present as colloidal-sized particles. A similar fraction (54 \mP 6%) of soluble cerium was retained on the ultrafilters. The fraction of platinum associated with the PM that has the potential to form truly dissolved (\ml10 kDa; \mA2 nm) species averaged 1.5 \mP 0.3%. Using ion-chromatographic methods it was determined that from 33 to 54% (41.5 \mP 6.8%) of the \ml10 kDa-sized platinum species were anionic in character, while in contrast virtually all (97.5 \mP 1.2%) of the cerium species were cationic or neutral in nature. Methanol extractions (24-hour Soxhlet, 0.45 \gmm filtered) released significantly more platinum (28 \mP 1.4% of total) and DCM extractions significantly less platinum (0.66 \mP 0.12% of total) than in water extractions. The parent Pt-FBC was not detectable in either methanol or DCM extracts of the diesel PM. The general speciation characteristics of FBC-platinum revealed in this study are consistent with findings of other studies of emissions from gasoline/diesel catalysts and those of environmental reservoirs.

File Size: 200K
Product Status: In Stock

Included in: SP-2024

See other papers presented at SAE 2006 World Congress & Exhibition, April 2006, Detroit, MI, USA, Session: Emissions Measurement and Testing (Part 4 of 4) Analyser and Test Facility Developments / Detailed Chemical Analysis

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