A multi-walled titanium-based nanotube array containing metal or non-metal dopants is formed, in which the dopants are in the form of ions, compounds, clusters and particles located on at least one of a surface, inter-wall space and core of the nanotube. The structure can include multiple dopants, in the form of metal or non-metal ions, compounds, clusters or particles. The dopants can be located on one or more of on the surface of the nanotube, the inter-wall space (interlayer) of the nanotube and the core of the nanotube. The nanotubes may be formed by providing a titanium precursor, converting the titanium precursor into titanium-based layered materials to form titanium-based nanosheets, and transforming the titanium-based nanosheets to multi-walled titanium-based nanotubes.