A new aluminophosphate phase, AlPO-NS, with a bellows-like morphology obtained from prolonged hydrothermal process or increased pH value of initial solution for synthesizing AlPO4-5

The aluminophosphate porous crystal, AlPO4-5, which has one-dimensional nanosized channels, was transformed and/or recrystallized after dissolving into a new aluminophosphate phase with a bellows-like morphology (AlPO-NS) during the extended hydrothermal reaction for the preparation of AlPO4-5. Increasing the pH value of the initial synthetic solution accelerated the formation of AlPO-NS. The empirical formula of the new crystalline phase of AlPO-NS per AlPO4 unit was AlPO4–0.21 Et3N–0.62 H2O, as compared with AlPO4-5: AlPO4–0.10 Et3N–0.26 H2O. The majority of the water molecules in the formula of AlPO-NS were derived from –OH groups bound to the aluminophosphate framework, confirmed by FT-IR spectroscopy.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A new AlPO compound was obtained by elongated hydrothermal reaction for solution synthesizing AlPO4-5. ► The new crystal has a bellows-like morphology named AlPO-NS. ► AlPO-NS has plenty terminal –OH groups.