Effect of Heat Treatment on Far Infrared Emission Properties of Tourmaline Powders Modified with a Rare Earth

Abstract

and W is OH À , F À , or O 2À ) powders and cerium nitrate as raw materials. The results of Fourier transform infrared spectroscopy (FTIR) show that rare earth Ce can enhance the far infrared emission properties of tourmaline. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism by which rare earth Ce acts on the far infrared emission property of tourmaline was systematically studied. The XPS spectra show that the Fe 31 ratio inside tourmaline powders after heat treatment can be raised by doping Ce. Moreover, it is showed that Ce 31 is dominant inside the samples but its dominance is replaced by Ce 41 outside. In addition, XRD results indicate the formation of CeO 2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far infrared emission properties of Ce-doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from the oxidation of Fe 21 (0.074 nm in radius) to Fe 31 (0.064 nm in radius) inside the tourmaline caused by the redox shift between Ce 41 and Ce 31 .

Effect of Morphology of Dispersed Nano-CeO2 on Far Infrared Emission Property of Natural Tourmaline

“…3), and leading to an apparent shrinkage of unit cell volume of tourmaline at low content of Ce. 17 The unit cell volume shrinkage will benefit the improvement of far infrared emission property of tourmaline. 17 23 …”

“…Therefore, the far infrared emission property of tourmaline needs further improvement to meet practical applications. In our previous research, 17 we found that Ce 4+ of CeO 2 oxidizes * Author to whom correspondence should be addressed. Fe 2+ to Fe 3+ inside the tourmaline, which leads to the unit cell volume shrinkage and consequently enhances the far infrared emission property of tourmaline.…”

“…Besides applications in gems, tourmaline is considered a promising ceramic material in the fields such as energy saving, environmental protection and health care. [14][15][16][17] According to the literatures, the higher the emissivity of the materials, the better the effect in the applications is Refs. [15,16].…”

Effect of rare earth Ce on the far infrared radiation property of iron ore tailings ceramics

“…The principle is based on the GaussianLorentzian function: valence's peak area ratio is proportional to its content ratio. Compared with experimental data and calculated spectra reported in literatures [32,34], the peaks of Fe 3+ (Fe2p 3/2 713.4 eV and Fe2p 1/2 726.4 eV) and Fe 2+ (Fe2p 3/2 711.7 eV and Fe2p 1/2 724.4 eV) can be easily identified, and the test curves were divided into four parts using of these binding energies. Then the peak area of corresponding valence can be obtained by XPSpeak software fitting.…”

“…This result has a certain correlation with the far infrared emissivity of samples. The most likely explanation for this is that the transformation from Fe 2+ to Fe 3+ oxidized by Ce 4+ because of the radius of Fe 2+ (0.078 nm) is larger than that of Fe 3+ (0.0645 nm) [32,33]. …”