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

我们希望制备基于锌掺杂氮氧化镓的无机材料，在可见光范围内具有更高的光催化活性，并延长寿命。材料体系中唯一的稀有元素Ga和Li一样丰富，是生产铝金属的副产品。该材料体系几乎没有危险，在水介质中非常稳定。与传统的液相合成方法不同，高结晶性纳米颗粒将在气相(化学气相合成，CVS)中合成，从而使我们能够将热后处理从团聚中分离出来，以退火缺陷。光吸收和电荷载流子的产生将通过尺寸效应和掺杂、低缺陷密度的电荷载流子分离和微结构变化的能带排列来优化。较大的比表面积为高效光催化活性提供了足够的活性中心。我们认为掺锌氧氮化镓是一个很有前途的体系，属于文献中报道的最活跃的体系。作为关键挑战，我们确定了从廉价来源(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，以及高效无贵金属助催化剂的开发和优化。我们希望利用CVS工艺和新型三元复合氧化物的分步光沉积的优点来应对这些挑战，并通过详细的结构和光催化活性的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的光谱表征(光电子能谱、低能离子散射、光电流谱)将使我们能够评估缺陷的作用并产生定量的结构-性质关联。

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.