High-Temperature Synthesis of Finely Dispersed Oxide Materials and C12A7:e Electrides in Carbon Nanoreactor Conditions
High-temperature synthesis of oxide materials is usually accompanied by sintering of initial nanoparticles and does not allow preparing them in a finely dispersed form. One of possible approaches to preserve the initial size of nanoparticles is the formation of core-shell materials where the shell does not react with the material of the oxide core under synthesis conditions. In the study we demonstrated using a number of examples [1-4] that construction of Oxide@C materials where the core is an oxide nanoparticle and the shell is made of carbon both makes it possible to preserve the size of oxide nanoparticles after treatment at high temperatures and perform solid-state reactions of the oxide core with various reagents inside the shell. The results of the following studies will be presented:
1) Phase transformations of the oxide core in TiO2@C system and products of its reactions with halocarbons .
2) Size effects and phase transformations of Al2O3@C core-shell materials in the temperature range up to 1400 °C .
3) Synthesis and properties of carbon-coated C12A7:e electrides at temperatures as high as 1600 °C and possible applications of such materials [3,4].