Formation of a 10$\mathring{\mathrm{A}}$ phase with halloysite structure under hydrothermal conditions with varying initial chemical composition

We studied the process of obtaining nanostructured halloysite by varying the parameters for creating the initial composition. The initial composition was synthesized by co-hydrolysis of (C$_3$H$_7$O)$_3$Al and (C$_2$H$_5$O)$_4$Si in the C$_6$H$_{14}$–NH$_3$ $\cdot$ H$_2$O system. Aluminum hydrosilicate with the composition Al$_2$Si$_2$O$_5$(OH)$_4$ was synthesized under hydrothermal conditions (220$^\circ$C, 2 MPa, 96 h). Particles of plate-like morphology with average length 100–200 nm and 60 nm thickness were obtained. The PXRD patterns revealed the presence of two phases. Plate-like kaolinites are found. Also we observed the formation of a halloysite-like phase. Studies of synthesized samples by IR spectroscopy and thermal analysis revealed the presence of organic-modified hydrosilicate with phase transition around 412$^\circ$C. The resulting phase is promising for studying the processes of adsorption and further exfoliation.