Efficient hydrogen production from irradiated aluminum hydroxides

• Published in: International journal of hydrogen energy 2019-02, Vol.44 (7), p.3737-3743
• Main Authors: Kaddissy, Josiane A., Esnouf, Stéphane, Saffré, Dimitri, Renault, Jean-Philippe
• Format: Article
• Language: English
• Subjects: Aluminum hydroxides; Analytical chemistry; Chemical Sciences; Defects; EPR; Hydrogen; Material chemistry; Radiation catalysis; Radiochemistry; Radiolysis
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.12.089

Radiation-catalysis is a well-known process leading to H2 production through radiolysis of adsorbed water on oxides. In this article, we show that common, easily accessible, hydroxides can be as much efficient for H2 production as the more efficient oxide identified until now. H2 radiolytic yields were determined from the same nanostructured hydrated samples that differ by their particle size (AlOOH L and AlOOH S for large and small particle size, respectively). The measured yields are of the order of 10−8 mol J−1. It means that such an irradiated material produces more efficiently H2 than an equivalent mass of water. H radicals, trapped electrons (F centers), and related O− centers were identified by electron paramagnetic resonance (EPR), at room and low temperature. Adsorbed water seems to play a role in the secondary processes of radical recombination, allowing a very efficient H2 production in these systems. This raises interesting questions about the energy transfer mechanism underlying this efficient hydrogen production and provide design lines for the design of efficient radiation-catalytic materials for H2 production. •Aluminum hydroxide, a model compound for other hydroxides, can be used for efficient H2 production under irradiation.•Hydroxides can be as much efficient for H2 production as the more efficient oxide identified until now.•Surprisingly, small-particle AlOOH releases less H2 then large-particle sized AlOOH.•Primary creation of defects does not really depend on particle size.