Zn-Ge oxynitride was synthesized using a solid-state reaction route under an NH3 atmosphere at 1023 K and then compared with a traditional temperature of 1173 K. XRD, XPS, BET and TEM techniques were employed to ascertain the microstructural properties. In addition, surface modifications with RuO2:Zn-Ge oxynitride were carried out to improve water splitting reaction under visible irradiation. X-ray diffraction analysis confirmed the stable wurtzite phase for the undoped and doped solid Zn-Ge solution. XPS reveals the binding energy for Ge, Zn and N-2 and the Eg < 2.5 eV and non stoichiometric rapport Zn/Ge. The morphology of these nitrides was solid nanoparticles with an average particle size of 20 nm and surface area below of 5 gm(-2). On the other hand, the catalytic activity was found to be higher with a RuO2-modified surface, as demonstrated by the water splitting reaction. (C) 2016 Elsevier Ltd. All rights reserved.