Production of molecular hydrogen from thermal and γquanta induced radiation thermal decomposition of water in the nano-Si/H₂O system

In this thesis, the amount of molecular hydrogen obtained from the radiation-thermal decomposition of nano-Si with particle size d=50 nm in contact with water vapor under the influence of thermal and γ-quanta (Cobalt 60, P=18.17 rad/sec), the rate of formation, and the regularity of the dependence of the energy output on the temperature of the general system (T=300, 373, 473, 573, 623, and 673K) were studied. The process of desorption of water adsorbed on the particle surface starts when the temperature of the system formed by nano-Si/H₂O ascends. Therefore, the dependence of the amount of molecular hydrogen obtained from both thermal and radiation-thermal decomposition of water in the reaction medium at high temperatures, the rate of formation, and the energy yield on the density of water were taken into consideration. In the Nano-Si/H₂O system, by keeping the mass of silicon in the reaction medium constant, the dependence of the molecular hydrogen's energy yield (G(H₂)=f(d_Si)) obtained from the radiation-heterogeneous decomposition of water on its mass has been proved. The energy yield of molecular hydrogen decreases with increasing particle size (d_Si). This reduction occurs more rapidly in the nano-scale (between 50-100 nm). This region corresponds to the nano-Si particle sizes, where the size effect is observed in the radiation-heterogeneous decomposition of water in the presence of Si.Free running distances of energy carriers (electron-hole pair and excitons) formed by the influence of γ-quanta on nano-Si were in the order of λ≤100 nm, and the efficiency of energy transport to surface levels increases in particles corresponding to this area.