Thermal deamination kinetics of the nickel-containing chabazite-like aluminophosphate, Ni(NH2-CH2-CH2-NH2)2(AlPO4)6(OH)2, deposition of nanocrystalline NiO particles

Thermogravimetrical analysis has been used to study the kinetics of thermal deamination of bis(ethylenediamine)nickel(II)-containing aluminophosphate (Ni-CHA) which is a precursor of nickel(II)-containing chabazite-like AlPO₄-34. The deamination occurs as a single-step kinetic process which is best described by the contracting cylinder model. The obtained activation energy of 200 kJ/mol is mainly a reflection of the strong Ni-N coordination bond. The thermal decomposition of Ni-CHA results in the deposition of crystalline NiO particles homogeneously dispersed in the AlPO₄-34 lattice. Average particle size was found to be about 5 nm. The study confirms that the thermal decomposition of amine complexes of Ni(II) encapsulated inside the microporous aluminophosphate host can be a suitable method for obtaining fine nano-oxide particles.