Pt–Ce-soot generated from fuel-borne catalysts: soot oxidation mechanism

Kamasamudram, Krishna; Makkee, Michiel

doi:10.1007/s11244-007-0183-1

Cited by 15 publications

(4 citation statements)

References 9 publications

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“…This last method is favorable for different reasons, such as (i) a continuous oxidation of the soot can be realized, decreasing the frequency of the regeneration that improves the fuel efficiency of the vehicle, and (ii) the durability of the filter is increased because of a limitation of the temperatures during the regeneration periods. − The contact between the catalyst and soot can be obtained according to different technologies. The catalyst can be (i) synthesized in the engine cylinder simultaneously to the formation of the soot using a fuel with a precursor catalyst additive according to the fuel-borne catalyst process (denoted as FBC), − (ii) deposited on the soot by the vaporization of molten salts placed up stream of the filter, − and (iii) coated on the filter material. − The two first methods favor the soot/catalyst weight ratio and their contacts, whereas a coated filter permits using a large variety of solid catalysts. The catalyst-coated filter process (denoted as CCF) is a candidate for application in the near future …”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] The contact between the catalyst and soot can be obtained according to different technologies. The catalyst can be (i) synthesized in the engine cylinder simultaneously to the formation of the soot using a fuel with a precursor catalyst additive according to the fuel-borne catalyst process (denoted as FBC), [11][12][13] (ii) deposited on the soot by the vaporization of molten salts placed up stream of the filter, [14][15][16] and (iii) coated on the filter material. [17][18][19] The two first methods favor the soot/catalyst weight ratio and their contacts, whereas a coated filter permits using a large variety of solid catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Microkinetic Approach of the Catalytic Oxidation of Diesel Soot by Ceria Using Temperature-Programmed Experiments. Part 1: Impact and Evolution of the Ceria/Soot Contacts during Soot Oxidation

et al. 2010

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The present study is dedicated to an experimental microkinetic approach of the catalyst oxidation of the diesel soot using a filter coated with ceria. To mimic the situation encountered in this process, mechanical ceria/soot mixtures have been prepared according to the tight and loose contact concepts described in the literature with ceria/soot ratio R > 1. Diesel soots prepared on an engine test bench and commercial soot have been used. The evolution of the ceria/soot contacts (via the amount of oxygen transferred from ceria to soot) with the progressive oxidation of the soot is followed using temperature-programmed experiments (denoted as TPEs) that provide the rate of CO2 and CO productions [denoted as R CO2 (T) and R CO(T)] during the increase in the temperature in helium in the range of 300−1100 K. During the first TPE, different surface processes implying pure soot and ceria contribute to R CO2 (T) and R CO(T), making the evaluation of the oxygen transfer difficult. It is shown that these difficulties are suppressed by performing, on the same ceria/soot sample, successive cycles constituted by a TPE followed by adsorption of O2 at 300 K that leads to the progressive oxidation of the soot. After three cycles, it is shown that, whatever the ceria/soot mixtures, the amount of oxygen that can be transferred from ceria to soot remains constant. This indicates that the ceria/soot surface contacts do not change during the soot oxidation, which is a conclusion consistent with recent literature data on environmental transmission electron microscopy (TEM). However, the amount of oxygen provided by ceria and available for the soot oxidation is dependent upon the type of ceria/soot mixtures, and this controls the performances of the catalyst evaluated by the decrease of the light-off temperature of the soot in a flow rate of 30% O2/He. These conclusions are used in part 2 (10.1021/ef100582w) to provide a detailed kinetic modeling of the TPE experiments for the different ceria/soot mixtures, focusing on the key role of the ceria/soot contacts on the rate of soot oxidation. This provides a consistent formalism to understand the impact of the types of catalyst/soot mixtures on the performances.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental Microkinetic Approach of the Catalytic Oxidation of Diesel Soot by Ceria Using Temperature-Programmed Experiments. Part 1: Impact and Evolution of the Ceria/Soot Contacts during Soot Oxidation

et al. 2010

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“…The inorganic and organic composition of fine PM emitted from diesel-powered motor vehicles, with and without after-treatment devises, has been the subject of several studies, − which has been used in numerous source apportionment studies, air-quality models, climate-change models, and health-effect studies; − however, very few studies have addressed the chemical characteristics of diesel PM when FBCs were used. ,, Even less information is available on the emission characteristics of diesel engine exhaust particles where a platinum−cerium bimetallic fuel additive was applied. The characterization of diesel engine emissions using a novel fuel amendment technology allows us to proactively understand future air pollution problems and prevent potential problems before the widespread adoption of the technology increases the inertia of the market to a level where even small changes are difficult.…”

Section: Introductionmentioning

confidence: 99%

Effects of a Platinum−Cerium Bimetallic Fuel Additive on the Chemical Composition of Diesel Engine Exhaust Particles

Okuda¹,

Schauer²,

Olson³

et al. 2009

Energy Fuels

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The use of a platinum-cerium bimetallic fuel additive has been proposed as a cost-effective strategy for reducing particulate matter (PM) and NO x emissions from diesel-powered engines. Although previous studies have demonstrated that the use of platinum-cerium bimetallic fuel additive reduced emissions from diesel engines, there have been no reported investigations of how the use of these fuel-borne catalysts (FBCs) impact the chemical and physical properties of diesel PM emissions. The present study demonstrates that the use of a platinum-cerium bimetallic fuel additive has a significant impact on the detailed chemical composition and size distribution of PM emitted from a diesel engine. Tests were conducted to explore the impact of different fuel concentrations of the fuel-borne catalyst at different engine-operating conditions. These tests were performed with a medium-duty diesel engine that was not equipped with exhaust gas recirculation or a diesel particulate filter (DPF). The results demonstrated that the use of the additive significantly reduced the emissions of PM 2.5 and carbonaceous species. The reduction was 34% for the PM 2.5 mass, 54% for the PM 2.5 elemental carbon, and 23% for the PM 2.5 organic carbon when 0.1 ppm Pt and 7.5 ppm Ce of the additive were used. Emissions of particle-phase metals originating from the additive had a significant contribution to particle matter emissions when 0.7 ppm Pt and 42 ppm Ce of the additive were used. The particle size distribution of platinum in the PM emissions was different from the size distribution of cerium. The cerium/ platinum ratio in the PM 2.5 diesel particle emissions ranged from 119 to 656, which was much higher than the ratio in the fuel additive that was 58.5 ( 5.6, indicating a higher penetration of cerium through the engine.

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“…Ce, Pt, Ce-Pt, and Fe-soot generated from their corresponding FBCs were studied by Krishna and co-workers, 36 of which, Pt-Ce soot is oxidized at much lower temperatures (275−300 °C) with O 2 in comparison to the other soot samples. Although ceria by itself can show great oxidative activity, the synergistic effect arising due to the combination of Pt with Ce seems to enhance the reaction rates.…”

Section: Clean Combustion Via Fuel Modification Strategiesmentioning

confidence: 99%

Advancements in In-Cylinder and After-Treatment Strategies for Mitigating Pollutants from Diesel Engines: A Critical Review

Da Costa,

Bukkarapu,

Fernandes

et al. 2024

Energy Fuels

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Although diesel after-treatment techniques demonstrate a substantial decrease in tailpipe emissions, the primary goal continues to be attaining nearly zero emissions to comply with current regulatory requirements and foreseeable imminent rigorous regulations. To achieve this objective, engine combustion systems and fuel formulations require fine-tuning. Taking insights from the recent literature, this review examines various processes, including homogeneous in situ methods, the incorporation of fuel-borne catalysts, and the use of biofuels. Despite progress in in-cylinder pollution mitigation techniques like low-temperature combustion, which exhibits substantial reductions in oxides of nitrogen (NO x ) and soot emissions, it is crucial to consistently advance technology to conform to evolving emission regulations and environmental concerns. A discussion is presented regarding the advantages and disadvantages of the homogeneous charge compression ignition (HCCI) mode and their potential for the future, focusing on biodiesel-fueled HCCI engines. The review assesses the effectiveness of thermal management strategies and engine design modifications that extend the operational range of HCCI engines powered by biodiesel in light of the inherent limitation of a restricted engine operating range. The review critically examines the merits and demerits of biofuels and HCCI systems and provides an essential analysis of current after-treatment approaches. With an imperative focus, the primary aim of this review is to ascertain modern catalysts designed explicitly for use in contemporary combustion systems. An exhaustive examination of the progress made in diesel oxidation catalysts, selective catalytic reduction techniques, lean NO x traps, diesel particulate filters, and catalyst regeneration is presented. The concluding remarks analyze the catalytic characteristics necessary for smooth incorporation with modern technological developments in various combustion systems.

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Pt–Ce-soot generated from fuel-borne catalysts: soot oxidation mechanism

Cited by 15 publications

References 9 publications

Experimental Microkinetic Approach of the Catalytic Oxidation of Diesel Soot by Ceria Using Temperature-Programmed Experiments. Part 1: Impact and Evolution of the Ceria/Soot Contacts during Soot Oxidation

Experimental Microkinetic Approach of the Catalytic Oxidation of Diesel Soot by Ceria Using Temperature-Programmed Experiments. Part 1: Impact and Evolution of the Ceria/Soot Contacts during Soot Oxidation

Effects of a Platinum−Cerium Bimetallic Fuel Additive on the Chemical Composition of Diesel Engine Exhaust Particles

Advancements in In-Cylinder and After-Treatment Strategies for Mitigating Pollutants from Diesel Engines: A Critical Review

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