Basic Definition of Precious Metal Catalysts for the Purification of Organic Waste Gas
A brief introduction to precious metal catalysts used in the purification of organic waste gas.
Basic Definition of Precious Metal Catalysts for the Purification of Organic Waste Gas
Noble metal catalysts utilize the catalytic activity of precious metals such as platinum (Pt) and palladium (Pd) to completely oxidize VOCs to CO₂ and H₂O at low temperatures of 200-400℃, making them the core materials for VOCs catalytic purification.
Basic Composition
Noble metal catalysts consist of three parts: the active component, the promoter, and the support.
Components | Materials | Functions |
Active Components | Pt、Pd、Rh | Provide catalytic activity, determining ignition temperature and conversion rate |
Additives | CeO₂、ZrO₂、La₂O₃ | Improve thermal stability and resistance to poisoning |
Carrier | Cordierite honeycomb ceramic + γ-Al₂O₃ coating | Provide structural support and high specific surface area |
Detailed Explanation of Components
Active Components:
Pt: High activity towards alkanes and aromatics, good thermal stability (content 0.1%-0.5%)
Pd: Excellent activity towards low-carbon VOCs, lower cost (content 0.1%-1.0%)
Industrially, Pt-Pd bimetallic combinations are commonly used, with ignition temperatures 20-40℃ lower than single metals.
Additives:
CeO₂: Improves oxygen storage capacity and thermal stability
ZrO₂: Improves resistance to sintering
La₂O₃: Improves resistance to sulfur poisoning
Carrier:
Cordierite honeycomb ceramic: Provides regular channels and low air resistance (100-400 cpsi)
γ-Al₂O₃ coating: Provides high specific surface area (150-250 m²/g) for dispersing precious metals
Typical Specifications
Parameters | Typical values |
Precious metal content | Pt 0.1%-0.5%，Pd 0.1%-1.0% |
Ignition temperature | 200-300℃ |
Operating temperature | 250-450℃ |
Space velocity | 10000-40000 h⁻¹ |
Summary
The composition of noble metal catalysts can be summarized as follows: the noble metal (Pt/Pd) provides activity, the promoter (CeO₂/ZrO₂) enhances stability, and the honeycomb ceramic + γ-Al₂O₃ provides structural support. The synergistic effect of these three components determines catalytic performance—the active component determines efficiency, the promoter determines lifetime, and the support determines pressure drop. Pt-Pd bimetallic catalysts are the mainstream choice for industrial VOCs purification.