project 12

Zn-doped Gallium Oxynitride Nanoparticles as Efficient Photocatalyst for Water Splitting

  • Prof. Dr. Martin Muhler, Ruhr-Universität Bochum, Institute for Technical Chemistry
  • Prof. Dr. Markus Winterer, Universität Duisburg Essen, Nanoparticle Process Technology

We want to produce inorganic materials based on zinc-doped gallium oxynitride with improved photocatalytic activity in the visible regime and extended lifetime. The only “rare” element in the materials system, Ga, is as abundant as Li, and a byproduct of the aluminum metal production. The material system has little hazardous potential and is probably of sufficient stability in aqueous media. Light absorption and charge carrier generation can be optimized by size effects and doping, charge carrier separation by low defect density and band alignment through microstructural variations. The large surface-to-volume ratio provides sufficient area for active sites for efficient photocatalytic activity. Therefore, we consider zinc-doped gallium oxynitride a promising model system with challenging materials optimization problems.

As key challenges we have identified the production of GaN from an inexpensive source such as Ga(acac)3, the control of local (dopants) and microstructure (dopants, core-shell, composites), and the development and optimization of efficient noble metal-free co-catalysts. We want to exploit the advantages of the CVS process and the step-wise co-catalyst photodeposition to meet these challenges and use detailed characterization of structure and photocatalytic activities to solve them. Especially, the quantitative determination of crystallinity and agglomeration and the correlation with photocatalytic activity combined with the comprehensive spectroscopic characterization (photoelectron spectroscopy, low-energy ion scattering, photocurrent spectroscopy) will allow us to identify responsible defect sites and to generate quantitative structure-property correlations.