Tracking in detail the synthesis of cadmium oxide from a hydroxyl gel using combinations of in situ X-ray absorption fine structure spectroscopy, X-ray diffraction, and small-angle X-ray scattering

The synthesis of cadmium oxide from a gel of cadmium hydroxide has been fol lowed in situ using unique combinations of X-ray diffraction (XRD), X-ray a bsorption fine structure (XAFS) spectroscopy, and small-angle X-ray scatter ing (SAXS). XRD and XAFS enable the crystallography, particle size, and loc al structure to be quantified as the hydroxyl gel converts into cadmium oxi de around 182 degrees C, SAXS measures the evolving microstructure, with ca dmium oxide growing dendritically in a fractal geometry, initially from rou gh nanoparticles. Major growth and densification takes place between 325 an d 550 degrees C. The implications for characterizing the precipitation of c admium oxide nanoparticles in zeolitic hosts are considered.