Proton-conducting silicophosphate sol-gel systems modified by water-and alcohol-soluble lowmolecular and high-molecular organic compounds (such as polyionenes, polyaminoguanidine, and organosilicon monomer) are synthesized by the sol-gel method. The physicochemical processes occurring in the course of the synthesis are investigated. It is revealed that the introduction of polyionenes into the sol-gel systems prevents the formation of silicon pyrophosphate crystals in the resulting silicophosphate nanocomposites (upon their heat treatment) and favors an increase in the protonic conductivity to 10 -2 S/cm over a wide range of temperatures (0-120 ° C).
Nanopowders of the composition (СeO2)1 – x(Sm2O3)x (x = 0.02; 0.05; 0.10; 0.20) were synthesized by two methods of chemical liquid-phase synthesis: co-precipitation of hydroxides with freezing and co-crystallization of salts with an average OCD size of ~ 8 – 11 nm, Sud = 40 – 83 m2/g. Based on them, ceramic nanomaterials with a cubic crystal structure of the fluorite type, with an OCR of ~ 65 – 81 nm (1300 °C), were obtained. The dependence of the phase composition, microstructure, and electric transport properties of the obtained samples on the content of Sm2O3 in a solid solution based on CeO2 and the synthesis method is revealed. It is shown that in the series (СeO2)1 – x(Sm2O3)x (x = 0.02; 0.05; 0.10; 0.20) a solid solution of the composition (CeO2)0.80(Sm2O3)0.20 has the highest ionic conductivity σ700 ºC = 2.7·10–2 Cm/cm. The resulting ceramic can be used as a solid electrolyte for medium-temperature fuel cells due to its physical and chemical characteristics.
The current-voltage characteristics and photoelectric properties of semiconductor structures containing Pd nanoparticles in thin films synthesized by the sol-gel method on an n-InP substrate have been investigated. The experimental results show that in presence of hydrogen the cut-off voltage changes. The photovoltage and photocurrent upon illumination of the structure with an LED (λ=0.9 μm) and pulsed exposure to hydrogen change, that was observed earlier for hydrogen-sensitive Pd/n-InP Schottky diodes. The prospects of using the structures under study as a sensitive element for hydrogen sensor are discussed. Keywords: Pd nanoparticles, sol-gel method, hydrogen, Schottky diode, hydrogen sensor.
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