In this work, we have synthesized a nano-heterostructure of TiO2 nanoparticles decorating TiO2 nanowires (TiO2 NPs/NWs). Both the TiO2 NPs and NWs show an anatase crystal phase with {101} facet predominately exposed. It is found that the ratio of NPs to NWs affects the dispersion of TiO2 NPs and their combination with TiO2 NWs, as well as the separation of photo-generated charges and further the photocatalytic activity of the material. The heterostructure with a TiO2 NPs to NWs ratio of 1:1 (NP0.5/NW0.5) shows high activity and excellent cycling stability in both Rhodamine B degradation and water splitting. A possible charge transfer mechanism on the TiO2 NPs/NWs hybrid has been proposed to clarify the correlation between material structure and performance. This work not only demonstrates the advantage of 0D-1D nano-heterostructures, but also provides a facile approach of designing and fabricating excellent catalysts for energy and environmental applications. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.