Effect of Heating/Cooling Rate on the Local Electronic Structure of Amorphous Calcium Carbonate

Abstract

Here, in the impact of heating/cooling rate was investigated on the formation of amorphous calcium carbonate (calcite) during sol-gel synthesis by probing local electronic structure. The amorphous calcium carbonate was synthesized by annealing precursor at 400oC at different heating/cooling rates i.e., 1.5 and 3oC /min. X-ray diffraction studies revealed amorphous nature at both heating/cooling rates. Fourier transformed infrared spectroscopic measurements characteristics bands in the spectra of both materials. Near edge X-ray absorption fine structure measurements at Ca L-edge, C K-edge and O K-edge were utilized to reveal the associated changes in the local electronic structure during synthesis. Local electronic structure investigation using near edge X-ray absorption fine structure measurements shows onset of moisture absorption on the surface particles when kept in the open environment.