Cation- and Anion-Substituted Potassium Manganese Phosphate, KMnP3 O9 : Luminescence and Photocatalytic Studies

Phosphates as multifunctional materials were of vital importance in the environmental and energy fields. In the present work, a new cyclophosphate, potassium manganese phosphate (KMnP3 O9 ) (hereafter KMPO), was prepared by solid state method. Cations (Ag+ and Cu2+ ) and anion (N3- ) were substituted into KMPO lattice via ion-exchange and solid state methods, respectively. The as-prepared materials were characterized by powder X-ray diffraction, SEM-EDS and UV-visible diffuse reflectance spectra. Rietveld refinement was carried out for parent material. All the prepared materials were found to crystallize in the hexagonal lattice and isomorphous with KCoP3 O9 . The nitrogen content in N3- -substituted KMPO was estimated by EDS and O-N-H analysis. The bandgap energy of the cation- and anion-substituted samples was lower compared to that of pristine KMPO. Gouy method was employed to determine the magnetic susceptibility of KMPO. The photoluminescence property of Mn2+ in all the samples was studied, and the color coordinates were calculated using CIE 1931 chromaticity. The photocatalytic activity of visible light active material, N3- -substituted KMPO, was examined against the degradation of methylene blue and methyl violet at ambient conditions.