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Rare-Earth manganites: surface-segregated platinum increases catalytic activity
Science (New York, N.Y.)
|October 15, 1976
Summary
Lanthanum lead manganite (La(0.7)Pb(0.3)MnO(3)) crystals with trace platinum exhibit enhanced catalytic activity. Platinum segregation on the surface significantly boosts performance compared to pure platinum catalysts.
Area of Science:
- Materials Science
- Catalysis
- Surface Chemistry
Background:
- Lanthanum lead manganite (La(0.7)Pb(0.3)MnO(3)) is a perovskite material with potential catalytic applications.
- Platinum is a well-known catalyst, but its high cost necessitates efficient utilization.
- Understanding the role of dopants and surface properties is crucial for optimizing catalytic performance.
Purpose of the Study:
- To investigate the catalytic activity of La(0.7)Pb(0.3)MnO(3) crystals doped with trace amounts of platinum.
- To determine the effect of platinum segregation on the surface of these crystals.
- To compare the catalytic performance of doped crystals with pure platinum catalysts.
Main Methods:
- Synthesis and preparation of crushed and etched La(0.7)Pb(0.3)MnO(3) crystals with varying platinum concentrations.
- Surface analysis techniques to quantify platinum segregation (e.g., XPS, EDX).
- Catalytic activity measurements under specific reaction conditions.
Main Results:
- La(0.7)Pb(0.3)MnO(3) crystals with as little as 0.005 atomic percent platinum showed significantly higher catalytic activity than pure platinum crystals.
- An almost 100-fold segregation of platinum was observed on the crystal surfaces.
- The surface platinum concentration of 0.5 atomic percent was sufficient to explain the enhanced activity.
Conclusions:
- Trace platinum doping in La(0.7)Pb(0.3)MnO(3) dramatically enhances catalytic activity.
- Surface segregation of platinum is the primary mechanism behind the improved performance.
- This finding suggests a cost-effective approach to developing highly active catalysts by utilizing minimal amounts of precious metals.
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