Effects of alumina powder characteristics on H2 and H2O2 production yields in γ-radiolysis of water and 0.4 M H2SO4 aqueous solution

The effects of powder characteristics on H2 and H2O2 productions in 60Co γ-radiolysis were studied in pure water and in 0.4 M H2SO4 aqueous solutions containing alumina powders. In 0.4 M H2SO4 solution, the H2 yields strongly depended on alumina structures and decreased in the order of α > θ > γ-alumina, although the specific surface areas increased as α < θ < γ. The yields increased with increasing specific surface area when compared among α-alumina. In pure water, similar dependence was observed but not as strong as that for 0.4 M H2SO4 solution. The H2O2 yields were strongly decreased by adding the alumina powders in both water and 0.4 M H2SO4 aqueous solution, although the amounts of decrease were almost neither correlated with specific surface areas nor structures. The enhancing H2 production was discussed in terms of the electron supply from alumina to aqueous solution as well as the adsorption of OH radicals on alumina surfaces.