Abstract Recently, black and grey titania in various morphologies have been intensively investigated for their high performance in photocatalytic H₂ generation. Here we use titania nanosheets (NSs) with a large percentage of (001) facets and hydrogenate them to activate suitable Ti³⁺-O_v defects for co-catalyst free H₂ generation. Key to a highly active NS-catalyst is the prevention of serious deformation and sintering during the thermal hydrogenation. In this work, we present a systematic investigation of different thermally treated NSs characterized by scanning electron microscope, high resolution-transmission electron microscopy, TEM-energy-dispersive x-ray, x-ray diffraction, electron paramagnetic response, x-ray photoelectron spectroscopy, and photocatalytic H₂ evolution performance. We describe how to achieve robust grey NSs with an intact two-dimensional shape that can endure hydrogenation at the required high temperatures. Due to a defined faceting, these optimized ‘grey’ NSs can produce photocatalytic H₂ at a higher rate than previously reported best performing grey nanoparticles—this in spite of having a lower Brunauer–Emmett–Teller than the reduced nanoparticles.