nano-sized alpo4-5 crystals: synthesis and characterization

molecular sieves and zeolites are materials whose crystalline frameworks form nanometer or subnanometer pores. a variety of different crystal structures are known having a range of pore sizes. because the pore sizes are usually smaller than 2 nm, they are classified as microporous materials. synthesis of microporous materials is usually conducted by the high temperature treatment (80-200 °c) of aqueous synthesis gels. the process of heating aqueous mixtures to elevated temperatures for crystallization is typically described as hydrothermal synthesis. a hydrothermal treatment has been used to synthesize nano-sized alpo4-5 (afi) crystals. the treatment involved three main steps: (1) to prepare a synthesis gel and let it get well mixed, then filling autoclave with the gel and sealing it; (2) crystallization at 180 ◦c for 6 h; and (3) calcination at 600 ◦c for 4 h to separate template materials. the crystals have been structurally characterized using x-ray diffraction (xrd), scanning electron microscope (sem), energy dispersive x-ray analysis (edax). the analyses show an acceptable fitness to the referred pattern. the sem analysis and scherer equation revealed that the size of the obtained alpo4-5 crystals was about 65 nm.