高分散的Pt促进氨分解中活性Fe_(x)N的形成  

Highly dispersed Pt boosts active Fe_(x)N formation in ammonia decomposition

作　　者：Keshia Saradima Indriadi 韩沛杰 丁世鹏 姚冰清 Shinya Furukawa 何迁 颜宁 Keshia Saradima Indriadi;Peijie Han;Shipeng Ding;Bingqing Yao;Shinya Furukawa;Qian He;Ning Yan(Department of Chemical and Biomolecular Engineering,National University of Singapore,Singapore 117585,Singapore;Joint School of National University of Singapore and Tianjin University,Fuzhou 350207,Fujian,China;Department o6f Materials Science and Engineering,National University of Singapore,Singapore 117575,Singapore;Institute for Catalysis,Hokkaido University,Sapporo 001‐0021,Japan)

机构地区：[1]新加坡国立大学化学与生物分子工程系,新加坡,新加坡 [2]新加坡国立大学与天津大学联合学院,福建福州350207 [3]新加坡国立大学材料科学与工程系,新加坡,新加坡 [4]北海道大学催化研究所,札幌,日本

出　　处：《Chinese Journal of Catalysis》2023年第7期297-305,共9页催化学报（英文）

摘　　要：在氢经济的背景下,氨分解在制氢中起着重要作用.铁基催化剂因价格低廉且活性适中而备受欢迎,对大规模应用具有吸引力.然而,铁基催化剂向更高活性Fe_(x)N物种的转化较慢,导致诱导期延长.为了解决该问题,本文研究了在氨分解中添加Pt对Fe_(x)N形成的影响.结果表明,即使添加少量(0.1 wt%)Pt,也能显著提高Fe_(x)N的形成速率,使其增加3倍以上.Pt通过反溢流促进H_(2)脱附,相反,反溢流暴露出更多发生氮化的Fe表面位点,导致Fe_(x)N的形成.高角度环形暗场扫描透射电子显微镜、X射线衍射和原位X射线吸收光谱表征揭示了Fe2N活性物质的形成.H_(2)程序升温脱附、H_(2)程序升温还原和原位X射线吸收谱证实了氢反溢流和溢流效应的存在.总之,本文加深了对铁催化剂在氨分解中活性物种形成机制的理解,为提高其催化性能提供了一个简单策略.Ammonia decomposition plays an important role in hydrogen production,especially in the context of a hydrogen economy.Fe‐based catalysts are a popular choice due to their affordability and moderate activity,making them attractive for large‐scale applications.However,the transformation of Fe‐based catalysts into more active Fe_(x)N species can be slow,resulting in a prolonged induction period.To address this issue,we investigated the effects of Pt addition on Fe_(x)N formation in ammonia decomposition.Our results show that even a slight Pt addition significantly enhances the Fe_(x)N formation rate,increasing it over threefold.Pt aids in H_(2) desorption via reverse spillover,which,in turn,exposes more Fe surface sites where nitridation occurs,leading to the formation of iron nitride.Characterization via High‐angle annular dark‐field imaging scanning transmission electron microscopy,X‐ray diffraction,and in situ X‐ray absorption spectroscopy(XAS)revealed the formation of Fe2N as active species,whereas temperature‐programmed hydrogen desorption,temperature‐programmed reduction by hydrogen,and in situ XAS supported the existence of H reverse spillover and spillover effects.Overall,our study provides an improved understanding of the active species formation mechanism of Fe catalysts in ammonia decomposition and offers a simple strategy for improving their catalytic performance.

关 键 词：氨分解 氮化铁 氮化 Pt促进 氢反溢流 

分 类 号：O643.32[理学—物理化学]