Synthesis and Characterization of Mesoporous, Nanostructured Zinc Aluminium Carbonate Layered Double Hydroxides (ZAC-LDHs) and Its Calcined Product (CZA-LDH)

Abstract

In the present study, Zinc Aluminium Carbonate Layered Double Hydroxides (ZAC-LDHs) with hydrotalcite like material are synthesized at different Zn2+/Al3+ molar ratios (R = 2:1, 3:1 & 4:1) by co-precipitation followed by hydrothermal method using cationic surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) as a soft template at constant pH 9. The Calcined Zinc Aluminium Carbonate LDH (CZA-LDH) sample is prepared by calcination of Zn3Al Carbonate-LDH at 450 °C for about 2 h. The materials obtained ZAC-LDHs (R = 2, 3 & 4) and calcined sample (CZA-LDH) are characterized by a set of powder X-Ray Diffraction (PXRD), N2 adsorption and desorption isotherms (Brunauer–Emmett–Teller BET), Fourier Transform Infrared Spectroscopy, Field Emission Scanning Electron Microscope with Energy Dispersive Spectroscopy (FESEM with EDS), Thermogravimetric Analysis (TGA and DTA) and high Resolution Transmission Electron Microscope (HR-TEM). The increase in intensity and sharpness of the peak from the XRD pattern confirms that all the synthesized materials of ZAC-LDHs (R = 2, 3 & 4) are crystalline in nature. Owing to more advantageous property called “memory effect”, the CZA-LDH reconstruct its original LDH structure by intercalating anions present in aqueous solution. From the XRD and BET surface analysis of data, the formation of mesoporous and nano structured crystalline material of ZAC-LDHs and CZA-LDH through simple and synergistic methods of co-precipitation and hydrothermal method at 120 °C using CTAB as a soft template is confirmed.