The use of titanium dioxide (TiO2) for photocatalytic applications has been intensively investigated for years due to appropriate electronic properties, chemical and photocorrosion resistance, as well as the low cost of the material [1]. Although TiO2 has a suitable conduction band position for the photocatalytic H2 formation reaction, the hydrogen evolution reaction from water on a TiO2 surface is kinetically hampered. To tackle this problem, typically decoration with noble metals such as Pt, Pd, Au that act as a co-catalyst is employed. However, these noble metals are costly and a variety of pathways for replacing these elements have been explored. One of the promising substitutes for noble metals are copper and copper-compounds. The fabrication of copper co-catalyst loaded TiO2 nanotubes is conventionally carried out by chemical methods such as hydrothermal, impregnation, photo-deposition and electrochemical deposition [2]. However, a most straightforward and unique method to modify anodic TiO2 nanotube properties is employing, instead of pure Ti metallic substrate, a Ti‐X alloy in the anodization process, were X is another metal. During anodizing the second metal can be simultaneously oxidized and doped into the TiO2 lattice (in substitutional or interstitial position), giving the nanotubes a specific functionality [3–5]. A number of such intrinsically doped nanotube arrays have been reported, namely using Nb, Ta, Ru and etc., alloyed in Ti [3–5].In this work, we grow intrinsically Cu doped TiO2 nanotubes (TiNTs) by self-organizing anodization of Ti-Cu binary alloys. We demonstrate that up to a copper concentration of 1.5 at.% in the alloy, self-ordered Cu2+-doped nanotubes can be grown. Under UV illumination the Cu2+ ion-doped oxide structures can be converted to nanotubes that carry metallic nanoparticles (NPs) uniformly decorated TiNTs. We investigate the formation of these metallic nanoparticles under UV illumination by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). The resulting intrinsic copper doped and decorated TiNTs provide a strongly enhanced photocatalytic activity for H2 evolution in comparison to pristine TiNTs. Key is the light induced conversion of the intrinsic Cu doping to metallic copper nanoparticles that act as a stable co-catalyst for H2 generation.[1] K. Lee, A. Mazare, P. Schmuki, Chem. Rev. 2014, 114, 9385–9454.[2] M. Janczarek, E. Kowalska, Catalysts. 2017, 7, 317-324.[3] P. Roy, C. Das, K. Lee, R. Hahn, T. Ruff, M. Moll, P. Schmuki, J. Am. Chem. Soc. 2011, 133, 5629–5631.[4] M. Altomare, K. Lee, M.S. Killian, E. Selli, P. Schmuki, Chem. - A Eur. J. 2013, 19, 5841–5844.[5] C. Das, P. Roy, M. Yang, H. Jha, P. Schmuki, Nanoscale. 2011, 3, 3094–3096. Figure 1