Rietveld refinement of sol–gel Na2Ti6O13 and its photocatalytic performance on the degradation of methylene blue

Abstract

We have refined single crystals of Na2Ti6O13 through the X-ray Rietveld method. The synthesis of the Na2Ti6O13 was carried out by sol–gel method at 70 °C, and the obtained gel was heat treated at different temperatures. Through different analytical techniques such as X-ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), Infrared Spectroscopy (FTIR), and Thermal Analysis (DTA/TGA), it was determined that Na2Ti6O13 can be prepared at low temperature (750 °C) by sol–gel method. The product crystallizes in rectangular shape micro-fibers, free of impurities. Rietveld refinement was performed using X-ray diffraction technique taking as basis a monoclinic cell with space group C2/m. The following refined parameters were obtained: a = 15.095(7) A, b = 3.745(3) A, c = 9.174(1) A, β = 99.01. Additionally, Na2Ti6O13 was tested as photocatalysts on the degradation of methylene blue (MB) under UV light. The degradation reaction follows a first order reaction model with kinetic parameters k = 0.0089 min−1, and t 1/2 = 78 min.