To date, hydrogen generation and storage are two separated processes. We report on a new concept where photocatalytically generated hydrogen is simultaneously stored in-situ within the material photo-generating hydrogen. To this aim, we successfully synthesised a "forest" of vertically aligned TiO2 nanotubes decorated with Pd nanoparticles acting as the hydrogen store. Upon illumination of TiO2, hydrogen was effectively generated and full storage of hydrogen within the Pd nanostructures was achieved within 100 min. This result demonstrates new avenues on the possibility of designing hybrid nanostructures for the effective use of hydrogen as an energy vector. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.