Zn-Ge oxynitride based nano-photocatalyst for hydrogen production under visible light

• Zn-Ge oxynitride with hexagonal structure was confirmed by X-Ray Diffraction analysis.
• The Kubelka-Munk transformation shows the emission for Zn-Ge oxynitride at 2.1 eV.
• The photocatalyst RuO2:Zn0.25GeN0.17O0.24 is viable for H2 production.

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 N2 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 g m−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.

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