H2 production by γ and He ions water radiolysis, effect of presence TiO2 nanoparticles

The effect of TiO₂ particles on the yield of H₂ formation under water radiolysis is measured. Irradiations were performed using a ⁶⁰Co γ−ray source as well as with He ions particles (4He2⁺) generated by a cyclotron with an external beam energy of 6 MeV. The resulting hydrogen as a stable product of radiolysis was measured by mass spectrometry. G(H₂) obtained for water radiolysis by He ions−irradiation in aerated and argon water are found to be 1.91 × 10⁻⁷ and 1.35 × 10⁻⁷ mol J⁻¹, respectively. In the presence of titanium oxide anatase−type dispersed in water, under He ions−irradiation, G(H₂) is found to increase slightly from 1.04 × 10⁻⁷ to 1.35 × 10⁻⁷ mol J⁻¹ by increasing the specific surface from 8 to 253 m²/g, respectively. Under γ-irradiation, G(H₂) is found to be 0.41 × 10⁻⁷ mol J⁻¹ close to primary yield of hydrogen in presence of OH. Radical scavenger. In addition, radiolysis of water adsorbed in the titanium oxide with low water content, which corresponds to a few layers of water sorbed onto the solid surface gives a huge values of the G(H₂). For the same amount of water, with using the dose absorbed by TiO₂ particles, for He ions-irradiation, G(H₂) increases from 14.5 × 10⁻⁷ to 35 × 10⁻⁷ mol J^-1 by increasing the surface area of TiO₂ nanoparticles from 4 to 52 m²/g, respectively. For γ−irradiation G(H₂) is found to be 5.25 × 10⁻⁷ mol J^-1 for the sample with 8 m²/g specific surface area.