Organic–inorganic hybrid hierarchical aluminum phenylphosphonate microspheres

•Hierarchical flower-like Al2(O3PC6H5)3·H2O microspheres were synthesized.•The growth mechanism relies on Ostwald ripening and oriented attachment.•The hierarchical nanoporous AlPO4 micro-flowers were obtained by sintering.•Peptide enrichment properties were demonstrated and proved to be promising.•A general synthesis procedure is developed for metal phosphonate spheres.

Organic–inorganic hybrid phenylphosphonates with hierarchical morphologies have attracted much attention due to their structural versatility for various applications including catalysis, adsorption, and biomedicals, however, so far there have been no reports of the synthesis and application of aluminum phenylphosphonate microspheres. Here, we report a hydrothermal method for the synthesis of the flower-like porous aluminum phenylphosphonate microspheres by using phenylphosphinic acid and aluminum nitrate as the precursors. The nano-flakes formed in the initial growing stage are believed to play a key role in the formation of aluminum phenylphosphonate micro-flowers. The self-assembly of the flower-like microspheres has been identified to involve a two-stage growth process: a synergistic Ostwald ripening and oriented nanosheets attachment. The resultant aluminum phenylphosphonate micro-flowers can be easily converted to mesoporous amorphous aluminum phosphates by high temperature treatment without causing any morphology deterioration. The hierarchical aluminum phenylphosphonate microspheres have been applied to enrich peptide. This versatile synthesis method would enable to synthesize other metal phosphonates/phosphates spheres with interesting architecture for the potential application in catalysis, energy storage and nanomedicine.

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