A TiO2 nanotube-based nanoreactor was designed and fabricated by facile two steps synthesis: firstly, hydrothermal synthesized SrTiO3 was deposited on TiO2 nanotubes (TiO2NTs). Secondly, the Au nanoparticles (NPs) were encapsulated inside the TiO2NTs followed by vacuum-assisted impregnation. The as-synthesized composites were characterized using Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Photoluminescence spectra (PL) and Ultraviolet-visible absorption spectroscopy (UV-vis). The photocatalytic performance was evaluated by the hydrogen evolution reaction. The results revealed that the SrTiO3 modified TiO2NTs confined Au NPs (STO-TiO2NTs@Au) achieved an enhanced hydrogen evolution rate at 7200 mu mol h(-1) g(-1), which was 2.2 times higher than that of bald TiO2NTs@Au at 3300 mu mol h(-1) g(-1). The improved photocatalytic activity could be attributed to the synergistic effect of the electron-donating of SrTiO3 and TiO2NTs confinement. The as-designed nanoreactor structure provides an example of efficient carriers' separation photocatalyst. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.