Radiation-catalysis is a well-known process leading to H-2 production through radiolysis of adsorbed water on oxides. In this article, we show that common, easily accessible, hydroxides can be as much efficient for H-2 production as the more efficient oxide identified until now. H-2 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 H-2 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 H-2 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 H-2 production. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.