AlPO4based

AlPO4-based materials are inorganic compounds and composites in which aluminum phosphate (AlPO4) forms the primary structural unit. They may be crystalline, such as berlinite-type AlPO4, or amorphous aluminum phosphate, and can also include doped or substituted variants, as well as composites with other oxides. Si-containing aluminophosphates, known as SAPO materials, are a notable family that combines silicon with the aluminophosphate framework.

The structure of AlPO4-based materials is characterized by strong Al–O–P linkages that create networks with varying degrees of porosity. Crystalline AlPO4 phases can exhibit quartz-like frameworks, while amorphous aluminum phosphate offers different textural properties. The materials are valued for thermal stability, chemical resistance, and adjustable acidity or basicity, which can be tuned by composition, crystallinity, and porosity.

Synthesis methods include precipitation from aluminum salts and phosphoric acid, hydrothermal or solvothermal crystallization, and sol-gel processing. Template-directed approaches using organic molecules or inorganic templates can produce mesoporous or highly organized structures. Post-synthesis treatments, such as calcination, help develop the desired porosity and phase composition.

Applications of AlPO4-based materials span catalysis, adsorption, and separation. They serve as catalyst supports and active catalysts in hydrocarbon processing, especially when doped with silicon or other elements (as in SAPO zeotype materials). Their porosity and surface properties also make them useful for gas separation, ion exchange, and water treatment. In ceramics and refractories, aluminum phosphate components contribute to bonding, thermal resistance, and chemical durability. Related materials include various aluminophosphate and SAPO systems with tailored acidity and pore structure.