Preparation and Characterization of Boron-Doped Nanodiamond

Boron-doped nanodiamond was prepared by a high-temperature vacuum-diffusion method. Thermogravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, Raman spectroscopy, and transmission electron microscopy were used to characterize the prepared material. Results show that the product mainly contains C, O, and B in mass fractions of 92.08%, 7.14%, and 0.78%, respectively. In addition to diamond (111)_D and (220)_D diffraction peaks, hexagonal diamond (100)_D diffraction peaks are also observed in the XRD pattern of the boron-doped product. The introduction of B atoms increases the defect content in the nanodiamond and causes the Raman G peak to move to 1620 cm⁻¹. B atoms are mainly present in two forms in the diamond lattice: substitutional carbon atoms in C-B bonds, and being bonded with impurity elements (such as B-O). The shape and morphology of the boron-doped nanodiamond particles (particle size of detonation nanodiamond, 2∼10 nm) exhibit no obvious changes compared to the pristine nanodiamond. However, a small amount of cubic diamond is observed. In conclusion, the initial oxidation temperature of the boron-doped nanodiamond increases by 175 °C, the oxidation rate is slower, and the thermal stability is improved.