Potassium antimony phosphates (K-Sb-P-O) exhibit different structural networks and thereforethey were studied as photocatalysts in the present investigation $ K_{5}Sb-{5}P_{2}O_{20}$was prepared by solid statemethod. Metal ions $Cu^{2+}$ and$ Sn^{2+}$), and non-metal anion,$ N^{3−}$, were substituted into the $ K_{5}Sb-{5}P_{2}O_{20}$ for possibleenhancement of photocatalytic activity. The precursor and substituted compounds were characterized bypowder X-ray diffraction, FT-IR, SEM-EDS and UV-Vis diffuse reflectance spectra. Nitrogen substitution into

$ K_{5}Sb-{5}P_{2}O_{20}$lattice was studied by O-N-H and XPS measurements. The photocatalytic activity of all the compoundswas studied by degradation of methylene blue and methyl violet. The ion-substituted $ K_{5}Sb-{5}P_{2}O_{20}$ haveshown higher photocatalytic activity against both the dyes. The role of reactive intermediate species producedin the photocatalytic reaction was studied using their appropriate scavengers.

In this work, we have studied the structural behavior of Fluortie-type (F-type) Ce-based oxides of compositions Ln₂Ce₂O₇ (Ln = Pr, Nd and Eu). F-type oxides can be considered as multi-functional materials due to the deficiency of anions. Pr₂Ce₂O₇ (PCO), Nd₂Ce₂O₇ (NCO) and Eu₂Ce₂O₇ (ECO) were prepared by ethylene glycol-assisted sol–gel method. The structural investigation of these oxides was carried out by Powder XRD and Rietveld refinement. All the materials were found to crystallize in the cubic lattice with space group $Fm\bar{3}m$. Raman spectra of these materials are reliable with their XRD data. The morphology and bandgap energy of all the samples were obtained from SEM and KM plot, respectively. The visible light photocatalytic performance of these oxides was examined against the degradation of methylene blue under ambient conditions. The photoluminescence property of the rare earth ionswas also studied, and the color coordinates were calculated using CIE 1931 chromaticity.