Catalyst carriers play a vital role in heterogeneous catalysis. They not only provide a place for the active components to disperse, but also regulate the catalytic performance through the interaction between the carrier and the active components. In the field of industrial catalysis, the choice of carrier materials directly affects the activity, selectivity and life of the catalyst. Alumina has become one of the most widely used catalyst carriers due to its high specific surface area, adjustable pore size distribution, good mechanical strength and rich surface chemical properties. According to statistics, more than 70% of industrial catalysts (such as hydrodesulfurization, automobile exhaust purification, Fischer-Tropsch synthesis, etc.) use alumina as a carrier or additive. According to statistics, about 70% of industrial catalysts use alumina as a carrier or additive.
Alumina has the following advantages as an ideal carrier: (1) high specific surface area and adjustable pore structure; (2) good mechanical strength and thermal stability; (3) abundant surface hydroxyl groups and adjustable acidity; (4) good compatibility with a variety of active components; and (5) relatively low cost and mature preparation process.
The following are examples of industrial applications:
1. Petroleum refining
• Hydrotreating catalyst
• Catalytic reforming
• Isomerization catalyst
2. Environmental protection
• Automobile exhaust purification
• VOCs purification
3. Chemical synthesis
• Fischer-Tropsch synthesis
• Dehydration reaction
Although alumina supports have been widely used, they still face other challenges, such as the decrease in specific surface area and phase transition at high temperatures, the difficulty in precisely controlling acidity, and the unclear mechanism of support-active component interaction in complex reaction systems.
In the future, the development direction of alumina carriers includes the following: guiding carrier design through computational simulation; developing new stabilization technology to extend carrier life; developing alumina carriers with multi-level pore structures; exploring the application of alumina in emerging fields such as electrocatalysis and photocatalysis. As Professor John Thomas, an authority in the field of catalysis, said: “The evolution of alumina carriers is a miniature epic of heterogeneous catalysis technology.” Against the backdrop of carbon neutrality and energy transformation, this classic material will surely be revitalized.