Synergistic effects in hydrogen production through water sonophotolysis catalyzed by new La2xGa2yIn2(1−x−y)O3 solid solutions

This work presents experimental data regarding hydrogen production by heterogeneous photocatalysis, sonocatalysis and sonophotocatalysis in water/ethanol solutions. Three new metal oxides solid solutions, LaGa0.5In0.5O3, La0.8Ga0.2InO3 and S-doped La0.8Ga0.2InO3 (S:La0.8Ga0.2InO3), have been synthesized and used as catalysts. Their action has been tested in diluted and concentrated suspensions wherein the content of ethanol, acting as sacrificial reagent, has been fixed to 10% in volume. The largest amounts of hydrogen have, always, been achieved from concentrated suspensions and by using S:La0.8Ga0.2InO3 as catalyst. Ultrasounds, generated by 38 kHz and 50 W piezoelectric transducer, were more effective than light coming from a 35 W Xe lamp. Moreover, the hybrid action of light and ultrasounds determined a remarkable synergistic effect on the hydrogen production. Therefore, sonophotocatalysis is a promising way of generating hydrogen from water/ethanol solutions. In the near future, a net hydrogen production is expected to be achieved by improving the proposed process efficiencies.