Synthesis and thermo-optical stability of o-methyl red-intercalated Ni–Fe layered double hydroxide material

In the present letter, an anionic azo dye, o-methyl red (2-(4-(dimethyl-amino) phenylazo) benzoic acid, MR), was incorporated successfully into the interlayer domain of Ni–Fe layered double hydroxide (LDH) by coprecipitation route. X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and simultaneous thermogravimetric and differential thermal analysis (TG-DTA) revealed the presence of supramolecular host–guest interaction between the host matrix and interlayer anionic dye guest with an expanded interlayer distance. The UV–visible diffuse reflectance (UV–VIS/DR) spectra showed that the dye-intercalated LDH had higher photostability than the pristine dye. Moreover, there was no significant change for the interlayer MR anions in the UV–VIS/DR spectra of the dye-intercalated sample after heating up to 200 °C, indicating that the thermostability of dye is markedly enhanced by the intercalation into the gallery domain of NiFe-LDH.