（12月1日）Novel Solid Catalysts for Ammonia Synthesis via Anion Defect Engineering

报告时间：2025年12月1日上午10:00-11:00

报告地点：福州大学阳光科技大厦二楼会议室

报 告 人：Prof. Masaaki Kitano（教授、东京科学大学）

主持人：安保正一 教授

组织单位：光催化重点实验室

联系人：林珍珍

联系方式：13675091109

报告摘要:

Catalytic ammonia synthesis is essential for producing synthetic fertilizers and various nitrogen containing chemicals. However, the industrial Haber-Bosch process requires high temperatures (400-500°C) and high pressures (10-30 MPa) because the bond energy of NºN bonds is extremely large. Currently, there is a strong demand for small-scale, on-site processes to produce green ammonia from hydrogen derived from renewable energy. Achieving this goal requires the development of novel catalysts that operate efficiently under mild conditions.

We have reported that electride and hydride materials significantly enhance the activity of transition-metal catalysts at low temperatures, underscoring the crucial role of hydride (H⁻) ions in ammonia synthesis. These materials have very low work function because of the formation of anionic electrons at anion vacancy sites. Furthermore, we have demonstrated that ammonia synthesis can be significantly promoted by nitride-based catalysts such as BaCeO_3-xN_yH_z and LaN via a vacancy-mediated mechanism, in which N₂ and H₂ molecules are activated separately at anion vacancies on the nitride support and at transition-metal surfaces, respectively—contrasting with conventional catalysts. By further extending this defect-utilization concept, we achieved efficient ammonia synthesis over Ba₃SiO_5-xN_yH_z even in the absence of any transition metal sites. In this catalyst, lattice H⁻ and N³⁻ ions readily desorb to form anion vacancies, and the electrons trapped at these sites activate H₂ and N₂ molecules, regenerating the lattice H⁻ and N³⁻ species. This vacancy formation–regeneration cycle serves as the driving force for ammonia synthesis over Ba₃SiO_5-xN_yH_z catalyst.

In this talk, I will first provide the background of catalytic ammonia synthesis. I will then present novel inorganic materials incorporating various anions (e⁻, H⁻, and N³⁻) as efficient catalysts. Finally, I will discuss the crucial role of anion sites in determining catalytic performance.

报告人简介：

Masaaki Kitano 教授，2006年博士毕业于日本大阪府立大学，师从安保正一教授。2007年至2009年在神奈川科学技术研究院从事博士后研究，2009年加入东京工业大学任助理教授，2013年晋升为副教授。2023年起任东京工业大学教授（2024年10月起任东京科学大学教授）。主要从事用于氨合成和其他加氢反应体系的电极、氢化物和氮化物催化剂的设计、合成和表征等的研究。在顶级期刊发表研究论文156余篇，被引15811次（Google Scholar，h指数：61）。