Gas-solid photocatalytic oxidation of dinitrogen to nitrogen oxides: Mechanism and kinetics

二氮气固光催化氧化成氮氧化物：机理和动力学

• 批准号: 502052591
• 负责人: Professor Dr. Gerd Bacher
• 金额: --
• 依托单位: Lehrstuhl Werkstoffe der Elektrotechnik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/502052591?language=en
• 关键词: Gas; solid; photocatalytic; oxidation; dinitrogen

The aim of the project is to attain a detailed understanding of the photocatalytic oxidation of N2 to nitrogen oxides in a gas-solid reaction. This recently discovered intriguing reaction could enable a completely new way for the sustainable synthesis of nitrates to be used for instance as (solar) fertilizers. Conducting the reaction in the gas phase has the significant advantage that the water-to-nitrogen ratio can be precisely controlled, suppressing the unwanted water oxidation and reduction as side-reactions. However, there is currently little knowledge of this reaction so this project will lay the foundation of a detailed mechanistic and kinetic understanding. This challenging goal thus requires complementary expertise from spectroscopy, catalysis, and reaction engineering working in concert.The first objective towards this end is to fully close the reaction’s material balance by identifying all reaction partners and products, including those of the corresponding reduction reaction. This will enable us to properly set up analytics and develop a screening protocol for routine evaluation of photocatalyst materials. As a systematic study on the topic is currently missing, suitable co-catalysts for nitrogen oxidation will be identified by systematically grafting metal ions (V, Mo, W, Fe, Pd, Pt, Cu) and oligomers onto TiO2, and evaluation of their photocatalytic activity. The metals are chosen based on proven catalytic activity in either the nitrogen oxidation or the decomposition of NO as the reverse reaction. TiO2 will be used as it has proven photocatalytic activity for this reaction and thereby suitable optoelectronic properties.The core objective is to unravel both, the mechanism, and the kinetics of the reaction in dependence of the employed reaction conditions (e.g., temperature, gas phase composition, and light intensity) . Using in situ and time-resolved laser spectroscopy, both the charge-carrier dynamics inside the semiconductor and their interaction with the catalytic sites will be interrogated. Raman and infrared spectroscopy are used to probe the surface of the catalyst and identify intermediate species and adsorption behavior. This information will be linked with data on the reaction rate and formed products to obtain a holistic mechanistic and kinetic model as foundation for future studies.

该项目的目的是获得在气-固反应中N2光催化氧化为氮氧化物的详细了解。最近发现的这一有趣的反应可以为硝酸盐的可持续合成提供一种全新的方法，例如用作（太阳能）肥料。在气相中进行反应具有显著的优点，即可以精确地控制水/氮比，抑制作为副反应的不希望的水氧化和还原。然而，目前对该反应的了解很少，因此该项目将为详细的机理和动力学理解奠定基础。因此，这一具有挑战性的目标需要光谱学、催化和反应工程方面的互补专业知识协同工作。为此，第一个目标是通过识别所有反应伙伴和产物（包括相应还原反应的产物）来完全关闭反应的物料平衡。这将使我们能够正确设置分析并制定筛选方案，用于光催化剂材料的常规评估。由于目前缺乏对该主题的系统研究，因此将通过系统地将金属离子（V、Mo、W、Fe、Pd、Pt、Cu）和低聚物接枝到TiO 2上并评价其光催化活性来确定用于氮氧化的合适的助催化剂。金属的选择是基于在氮氧化或NO分解作为逆反应中已证实的催化活性。将使用TiO 2，因为它已被证明对该反应具有光催化活性，从而具有合适的光电性能。核心目标是根据所采用的反应条件（例如，温度、气相组成和光强度）。使用原位和时间分辨激光光谱，半导体内部的电荷载流子动力学及其与催化位点的相互作用将被询问。拉曼和红外光谱用于探测催化剂的表面并鉴定中间物种和吸附行为。这些信息将与反应速率和形成的产物的数据相联系，以获得整体的机理和动力学模型，作为未来研究的基础。