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.

► This study presents the H2 production by γ and He ions water radiolysis. ► They were determined with a MKS MinLab mass spectrometer. ► This study done the effect of the specific surface area of titanium oxide on the final production of H2. ► The present work studies on the formation of H2 for the first time in TiO2 under He ions-irradiation.