Uniform NaTaO3 ca. 15 nm and ca. 70 nm nanocrystals were synthesized via a novel surfactant-free solvothermal reaction. The acidic alkoxide hydrolyzation leads to small size and high surface area particles. The different size of the nanocrystals was controlled by altering concentration. The alkoxide-based synthetic route leads to small particle size and high surface area, which improved the charge separation and migration of photogenerated carriers and benefited the surface chemical reaction of catalysts. As a result, the high total yield of photocatalytic water splitting hydrogen generation was obtained, which was as high as 3.106 mmol h(-1) g(-1). Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.