基于第一性原理的Fe(111)/Al_(2)O_(3)(0001)界面稳定性研究  

Stability of Fe(111)/Al_(2)O_(3)(0001)interface based on first principles

作　　者：王浦璠 邓道繁 陈果 张慧宁[1] 廖春发[1] WANG Pufan;DENG Daofan;CHEN Guo;ZHANG Huining;LIAO Chunfa(Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China)

机构地区：[1]江西理工大学材料冶金化学学部,江西赣州341000

出　　处：《有色金属科学与工程》2024年第2期158-166,共9页Nonferrous Metals Science and Engineering

基　　金：国家自然科学基金地区基金资助项目(52064020)。

摘　　要：稀贵金属催化剂催化甲烷分解效果显著但成本较高,为此,探寻低成本催化剂是实现其工业化推广的重要课题。铁基催化剂具有耐高温、价格低、性能好等优点,目前针对铁基催化剂的表面机理研究较少,催化剂界面组成及结构稳定性仍没有统一的观点。本研究基于密度泛函理论(DFT),利用第一性原理计算表面能、态密度、差分电荷密度,研究Fe(111)/Al_(2)O_(3)(0001)界面稳定性,并探讨不同端面的催化剂形成机制。结果表明:O端界面的吸附能和电荷浓度大于Al1和Al2端界面,O原子周围电荷聚集明显;Al_(1)和Al_(2)端界面的Fe和Al之间形成微弱金属键,而O端界面的Fe和Al之间形成共价键、金属键和离子键,O端共价键强度高于Al_(1)和Al_(2)端界面。因此,O端Fe/Al_(2)O_(3)催化剂相比于其他端面结合更加紧密,同时表现出更理想的催化效果,上述研究结果为制备Fe/Al_(2)O_(3)催化剂及研究其界面的形成机制提供理论基础。Rare and precious metal catalysts have remarkable effects on methane decomposition,but the cost is high,so that it is an important task to explore low-cost catalysts to realize their industrialization and popularization.Iron-based catalysts have the advantages of high-temperature resistance,low price and good performance.At present,there is little research on the surface mechanism of iron-based catalysts,and there is still no unified view of catalyst interface composition and structural stability.In this study,based on density functional theory(DFT),the stability of the Fe(111)/Al_(2)O_(3)(0001)interface was studied by first principles,and the formation mechanism of the catalyst with different end faces was discussed.The results of surface energy,state density and differential charge density analysis showed that the adsorption energy and charge concentration at the O-terminal interface were greater than those at the interface of Al1 and Al2,and the charge accumulation around the O atom was obvious.Weak metal bonds were formed between Fe and Al at the interface of Al_(1) and Al_(2),while covalent,metallic and ionic bonds were formed between Fe and Al at the interface of the O terminal.The O terminal covalent bond strength was also higher than the Al_(1) and Al_(2) terminal interfaces.Therefore,the O-end Fe/Al_(2)O_(3) catalyst was more tightly bound than other end faces,and would also show a better catalytic effect.The above research results provide a theoretical basis for preparing the interface formation mechanism of Fe/Al_(2)O_(3) catalyst。

关 键 词：密度泛函理论 表面能 金属催化剂 态密度 差分电荷密度 

分 类 号：TG113.12[金属学及工艺—物理冶金]