Non-solvent displacement nonaqueous precipitation method for core-shell materials preparation: Synthesis of C@ZrSiO4 black pigment

Abstract

A novel non-solvent displacement-nonaqueous precipitation method was developed for the preparation of core-shell materials by considering C@ZrSiO4 black pigments synthesis as the case. The effects of the impregnation time, precursor concentration, and carbon content on the synthesis and coloration of the C@ZrSiO4 pigment and the mechanism of this method were investigated via X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and CIELAB colorimetry. The results showed that the optimal impregnation time, precursor concentration, and carbon content were 24 h, 1.5 mol/L, and 9 wt%, respectively. C@ZrSiO4-encapsulated pigments prepared by a non-solvent displacement-nonaqueous precipitation method have a uniform and dense shell-encapsulated zircon layer with a thickness of 10–20 nm. The size of C@ZrSiO4 encapsulated pigments was 50–210 nm, without particle agglomeration. This uniform and dense encapsulation facilitated an excellent color-rendering effect in the high-temperature glaze, and the chromaticity values of the glaze were L* = 35.05, a* = 0.34, and b* = 1.08. The alkyl halide elimination non-hydrolytic heterocondensation reaction ensured the formation of a uniform precipitate along the surface of the carbon particles with Si–O–Zr bonds as the skeleton. The introduction of the non-solvent kerosene ensured the complete, uniform, and dense progress of the precipitation process to form a C@ZrSiO4 pigment with a high-quality core-shell structure. The non-solvent displacement-nonaqueous precipitation method might be an extremely promising method for preparing core-shell structural materials.