Gradient distribution of cations in rhabdophane La0.27Y0.73PO4·nH2O nanoparticles

The structure of gradient rhabdophane nanoparticles of variable composition (La,Y)PO₄·nH₂O obtained by precipitation is considered. According to the data of HAADF TEM and EDX mapping using the Abel inversion procedure, it was shown that there is an inhomogeneous distribution of yttrium and lanthanum atoms in the particles from the central part to the periphery. At the same time, the nominal composition of both individual nanoparticles and the entire sample meets the value specified during synthesis within the error of the method – La_0.27Y_0.73PO₄·nH₂O. According to SAXS data, it was determined that in the particles of (La,Y)PO₄·nH₂O, there is a redistribution of scattering densities, which is caused by an increase in the fraction of YPO₄ in the peripheral region of the particles. The observed effect of the distribution of cations over the particle made it possible to determine the size of the gradient layer, which reaches 50 % of the total particle size.