Synthetic magnesium silicate hydroxide nanoparticles coated with carbonaceous shell in subcritical water condition

Under subcritical water condition, the synthesis process of magnesium silicate hydroxide (MSH) and the decomposition process of oleic acid were simultaneously carried out, and the MSH nanoparticles coated with a carbonaceous shell on the surface were prepared. The characterization results of scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) indicate the formation of the carbonaceous shell and both granular and schistose shape of nanoparticles. This shell is characterized by using the Raman spectroscopy, Fourier transform infrared (FTIR) spectrum, and X-ray photoelectron spectroscopy (XPS). The results indicate the non-existence of CC sp3 bond and the high content (up to 72%) of CH sp3 bond. Besides, the carbonaceous shell is composed of amorphous and turbostratic carbon, which could be attributed to the decomposition of oleic acid, then followed by polymerization and aromatization of decomposition products.