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CeO2-based catalysts with engineered morphologies for soot oxidation to enhance soot-catalyst contact
Paolo Miceli1, Samir Bensaid1, Nunzio Russo1
1Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy.
Nanoscale Research Letters
|June 19, 2014
Summary
Three-dimensional self-assembled cerium oxide stars significantly enhance soot oxidation in diesel particulate filters. These stars offer high surface area and contact points, reducing oxidation temperatures and improving catalytic efficiency.
Area of Science:
- Materials Science
- Catalysis
- Environmental Engineering
Background:
- Morphology is crucial in solid/solid catalysis, particularly for soot oxidation where contact points are critical.
- Diesel particulate filters (DPFs) require efficient catalysts to oxidize soot, reducing harmful emissions.
- Existing cerium oxide morphologies have limitations in surface area or contact point availability for optimal soot oxidation.
Purpose of the Study:
- To investigate and compare the efficacy of three distinct cerium oxide morphologies as catalysts for soot oxidation.
- To evaluate the impact of cerium oxide morphology on catalytic activity, surface area, and contact point availability.
- To identify the most effective cerium oxide morphology for enhancing soot oxidation in conditions relevant to DPFs.
Main Methods:
- Synthesis and characterization of three cerium oxide morphologies: nanofibers, solution combustion synthesis, and self-assembled (SA) stars.
- Evaluation of catalytic performance for soot oxidation under tight and loose contact conditions.
- Measurement of specific surface area, microporous volume, and crystallite size for each morphology.
- Determination of the temperature of non-catalytic soot oxidation and T10% onset temperature.
Main Results:
- Self-assembled cerium oxide stars exhibited the highest specific surface area (105 m²/g) and superior soot oxidation activity.
- SA stars reduced the soot oxidation temperature from 614°C to 403°C (tight contact) and 552°C (loose contact).
- SA stars demonstrated the lowest T10% onset temperature, indicating higher intrinsic catalytic activity, even after ageing.
Conclusions:
- Three-dimensional self-assembled cerium oxide stars are highly effective catalysts for soot oxidation due to their morphology.
- The high surface area and increased contact points of SA stars enhance redox cycling and catalytic efficiency.
- These findings support the potential application of SA cerium oxide stars in real-world diesel particulate filters.
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