The application field of materials based on lanthanum orthophosphate (LaPO4) including nanomaterials, has been permanently extending recently. The high level of mechanical properties and the compatibility with numerous oxides make it possible to consider the possibility of using lanthanum orthophosphate as a composite material for construction purposes. This application is particularly promising when nanoparticles with quasi-1D morphology (nanorods) are used. The high isomorphic capacity of the LaPO4-based phase for alkaline-earth ions and ions of lanthanides and actinides, high chemical stability, and high radiation hardness make promising the application of this compound as a matrix for immobilization of radioactive wastes.
The possibility of obtaining lanthanum phosphate (LaPO4) by the hydrothermal method is considered in the work. Effects of pH, temperature and time of processing of hydrothermal synthesis on the morphology and structure of monostructured lanthanum phosphate are studied. It has been established that, with the increase of pH, the morphology of phosphate changed, the size of the crystallites increased, while the crystal structure changed from hexagonal to monoclinic.
The catalytic activity of nanostructured low-percentage Mg-Ni-Co-catalysts based on high-temperature KT-11-TO grade fiberglass obtained by “solution combustion” (SC) method was studied at carbon dioxide conversion of methane (CDCM). The physico-chemical characteristics of samples were studied using X-ray diffraction phase analysis, temperature-programmed reduction (TPR) and transmission electron microscopy (TEM). The X-ray phase method showed the formation of several phases during the synthesis: NiCo2O4, 3CoO·5NiO, MgO, and Co3O4. According to TEM, active catalyst particles have a size of 5-10 nm proving the nanoscale size of the active component. TPR method showed the shift of maximum hydrogen absorption to higher temperatures. Apparently, it occurs due to the interaction of the active components with the carrier till the new phase formation. On the basis of the gas chromatographic analysis the high activity of fiberglass catalysts at the carbon dioxide conversion of methane into synthesis gas with a conversion of the initial components close to ~ 100% was disclosed. The optimal technological conditions for the CDCM process were established – a temperature in the range of 850-900°С, the volumetric rate of initial reactants 4000-10000 h-1 with a ratio of methane to carbon dioxide equal to 1.
Preparation of synthesis gas by methane dry reforming on fiberglass catalysts
