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

我们希望生产基于锌掺杂氧化氮化镓的无机材料，该材料在可见光区具有改进的光催化活性和延长的寿命。材料系统中唯一的稀有元素Ga和Li一样丰富，是铝金属生产的副产品。该材料体系危险性小，在水介质中足够稳定。与传统的液相合成路线不同，高结晶纳米颗粒将在气相合成（化学气相合成，CVS），使我们能够将热后处理与团聚退火缺陷分离开来。光吸收和载流子产生将通过尺寸效应和掺杂、低缺陷密度的载流子分离和微结构变化的能带排列来优化。大的表面体积比为有效的光催化活性提供了足够的活性位点面积。我们认为锌掺杂氧化氮化镓是一个很有前途的体系，它属于文献中报道的最活跃的体系。作为关键挑战，我们已经确定了从廉价来源（如Ga(acac)3）生产GaN，局部（掺杂剂）和微观结构（掺杂剂，核壳，复合材料）的控制，以及高效的无贵金属共催化剂的开发和优化。我们希望利用CVS工艺和分步光沉积新型三元混合氧化物的优势来应对这些挑战，并利用结构和光催化活性的详细表征来解决这些问题。特别是，结晶度和团聚的定量测定以及与光催化活性的相关性结合综合光谱表征（光电子能谱，低能离子散射，光电流能谱）将使我们能够评估缺陷的作用并产生定量的结构-性能相关性。

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 sufficiently stable in aqueous media. In contrast to conventional synthesis routes in the liquid phase, highly crystalline nanoparticles will be synthesized in the gas phase (chemical vapor synthesis, CVS) allowing us to decouple thermal post-treatment to anneal defects from agglomeration. Light absorption and charge carrier generation will 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. We consider zinc-doped gallium oxynitride a promising system, which belongs to the most active systems reported in literature. 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 photodeposition of novel ternary mixed oxides 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 assess the role of defects and to generate quantitative structure-property correlations.