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Updated: Feb 11, 2026

Organic Structure-directing Agent-free Synthesis for *BEA-type Zeolite Membrane
Published on: February 22, 2020
Controllable Synthesis of Polyhedral Fe₃O₄ Hollow Spheres Using Hexamethylenetetramine as Structure-Directing Agent
Abstract:
Polyhedral Fe₃O₄ hollow spheres were synthesized using hexamethylenetetramine as structure-directing agent and the effect of hexamethylenetetramine on the morphology was investigated in detailed. The comparison for samples prepared with and without hexamethylenetetramine indicated that hexamethylenetetramine played a vital role in the formation process of the hollow polyhedral structure. The formation process and growth mechanism of Fe₃O₄ spheres with hollow polyhedral morphology were preliminarily explored according to a detailed time-dependent morphology and structure evolution. It was deduced that the hollow polyhedral structure can be ascribed to the cooperation of oriented aggregation and Ostwald ripening mechanisms. The as-prepared Fe₃O₄ hollow spheres with polyhedral structures which possess high magnetization saturation value (73 emu/g) at room temperature, large cavity and huge specific surface area (57.12 m2·g–1) are expected to have wide potential applications, for example in the drug delivery process, magnetic separation and waste treatment in the future.
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