engleski

Impact of cadmium and phosphate ions on the hematite nanorings formation

It has been suggested that the addition of divalent metal cations during the hydrothermal synthesis of hematite (alpha-Fe2O3) in the presence of phosphate ions has a strong impact on the hematite morphology, crystal growth and dissolution (Gotić et al., J. Mol. Struct. 993 (2011) 167). In this work, the same system was modified with divalent cadmium ions and the impacts of cadmium and phosphate ions on the hematite nanorings formation have been studied. It has been found that formed hematite and akaganeite (beta-FeOOH) precipitates did not contain any trace of cadmium impurities. On the contrary, the modification with divalent cadmium cations changes the (PO4)3-/Fe3+ molar ratio in the system. Upon the addition of cadmium ions the (PO4)3-/Fe3+ molar ratio changes from 0.036 in a pure system to 0.051 in the cadmium modified system. The relative increase of phosphate concentration at earlystage of precipitation induced the change of spindle to spherical morphology and formation of the poorly crystallised akaganeite-like phase. The appearance of akaganeite-like phase directly correlated with the delay in the crystallisation of hematite. Besides, the relative increase of phosphate concentration has the prevailing effect for the change of spindle to pseudosphere and nanotube to nanoring particle morphologies.

hematite ; nanorings ; cadmium ions ; phosphate ions

nije evidentirano