Application of Activated Alumina in Catalyst Supports
Briefly introduces the application of activated alumina in catalyst supports.
Application of Activated Alumina in Catalyst Supports
Activated alumina is the most widely used catalyst support material in industrial catalysis. Its high specific surface area and tunable pore structure make it an ideal substrate for loading various catalytically active components.
Support Functions
Activated alumina functions through the following mechanisms:
Dispersion: High specific surface area (200-400 m²/g) ensures high dispersion of active components.
Stabilization: The pore structure restricts the high-temperature sintering of active components.
Synergistic Effect: Surface acidity/alkalinity modulates catalytic performance.
Performance Requirements
Specifications | Requirements | Explanations |
Specific Surface Area | 150-300 m²/g | Ensuring dispersion of active components |
Pore Volume | 0.3-0.8 cm³/g | Providing space for loading active components |
Pore Size | 5-15 nm(Mesoporous) | Facilitating diffusion |
Crystal Phase | γ-Al₂O₃ | Most commonly used |
Thermal Stability | 600-900℃ | Tolerates reaction and regeneration temperatures |
Impurities | Na₂O≤0.05% | Alkali metals reduce thermal stability |
Shape | Strip, spherical, clover-shaped | Select according to reactor |
Typical Applications
Hydrogenation Catalyst Support
Activated alumina is the primary support for hydrodesulfurization (HDS), hydronitrogenation (HDN), and hydrocracking catalysts, loading active components such as Co-Mo and Ni-Mo. The support must possess a hierarchical pore structure with both mesopores and macropores to accommodate heavy oil molecules and prevent pore blockage.
Automotive Exhaust Gas Purification Catalyst
In three-way catalytic converters, activated alumina is loaded with precious metals such as platinum, palladium, and rhodium, while rare earth elements such as lanthanum and cerium are added to suppress high-temperature phase transitions and ensure continued activity at 800-1000℃.
Reforming Catalyst Support
In catalytic reforming, activated alumina is loaded with platinum-rhenium or platinum-tin bimetallic compounds. The support must possess moderate acidity and good thermal stability to balance metal and acid functions.
Clause Sulfur Recovery Catalyst
In the Claus process, activated alumina catalyzes the reaction of H₂S with SO₂ to produce elemental sulfur. The support must have a high specific surface area and suitable pore size, while also being resistant to sulfur corrosion.
SCR Denitrification Catalysts
Some medium- and low-temperature SCR catalysts use activated alumina as a support, loaded with vanadium, tungsten, or transition metal oxides, for flue gas denitrification.
Summary
Activated alumina is a core support material in industrial catalytic processes such as hydrogenation, tail gas purification, and reforming. Its high specific surface area, tunable pore structure, and good thermal stability are its three major advantages. Selection requires matching specific surface area, pore size, shape, and purity parameters according to the reaction type to achieve the optimal combination of support and active components. We are a Chinese supplier of activated alumina. For more information, please contact us via email at annayu@169chem.net or WhatsApp at +8618909016373.