Preparation of CdS coatings on the inner surface of silica aerogels by single-source metal-organic chemical vapor deposition at atmospheric pressure

CdS coatings are deposited on the external and inner surfaces of silica aerogels with a single-source metal-organic chemical vapor deposition method at atmospheric pressure. Thermogravimetry analysis and differential scanning calorimetry experiments are used to investigate the thermal behavior of silica aerogels, and the sample treated at 500 oC for 120 min has been found to possess the lowest density. The densities and morphologies of the silica aerogels under the different treatment temperatures are also studied. The CdS coatings are deposited on the inner surface of the silica aerogels with a 4 l/min flow of Ar gas. The procedure for the preparation of the CdS coatings on the inner surface is reported in details. The surface morphologies of the CdS-coated silica aerogels are analyzed by scanning electron microscopy. The results of the energy dispersive X-ray spectroscopy and X-ray diffraction analysis demonstrate that the CdS coatings are composed of cadmium and sulphur with an approximately atomic ratio of 1:1, and they are hexagonal structures.