SiO_(2)担载的Au@Pt与Au@Pd核壳型双金属催化剂的结构热稳定性对比研究  

Comparison Study of Structural Thermostability of SiO_(2) Supported Au@Pt and Au@Pd Core-Shell Nanoparticles

作　　者：张晓慧 关桥桥 孙梅 路军岭 Xiaohui Zhang;Qiaoqiao Guan;Mei Sun;Junling Lu(School of Chemistry and Materials Science,Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes,University of Science and Technology of China,Hefei 230026,China;Hefei National Research Center for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学技术大学化学与材料科学学院,安徽省教育厅表界面化学与能源催化重点实验室,合肥230026 [2]中国科学技术大学合肥微尺度物质科学国家研究中心,合肥230026

出　　处：《Chinese Journal of Chemical Physics》2023年第2期132-140,I0054,共10页化学物理学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(No.22025205);the National Key R&D Program of China(2021YFA1502802);the Fundamental Research Funds for the Central Universities(WK2060000038);Users with Excellence Program of Hefei Science Center CAS(2019HSC-UE016).

摘　　要：双金属纳米颗粒催化剂因其在众多化学反应中的广泛应用而备受人们关注.其催化性能与双金属颗粒的结构密切相关.在原子水平上理解其结构热稳定性对设计高稳定性双金属催化剂具有重要意义.本文利用选择性原子层沉积技术,在SiO_(2)载体上精准地构筑了Au@Pt与Au@Pd核壳型催化剂,其中Au核尺寸约为5.1 nm,Pt或Pd的壳层厚度均控制在两个原子层左右.使用谱学、电镜表征对比其在氢气氛围下的结构热稳定性,发现相较于Au@Pd/SiO_(2)核壳型催化剂,Au@Pt/SiO_(2)更难于向合金结构转变,展现出了更为优异的结构热稳定性.此外,550℃高温还原后,两种催化剂均维持其颗粒尺寸,无明显聚集现象,展现出优异的抗烧结性能.Au@Pt/SiO_(2)核壳型催化剂具备更好的结构热稳定性,可能是源于壳层Pt原子更高的熔点以及Au-Pt之间更小的晶格失配.该工作为理解双金属纳米颗粒在高温下的热力学行为的内在机制提供了参考.Bimetallic nanoparticle(NP)catalysts have attracted long-standing attentions for their wide applications in a broad range of chemical reactions.Their catalytic performance tightly relies on the structure of bimetallic NPs.Atomiclevel understanding of their structural thermostability is of great importance for developing advanced bimetallic catalysts with high stability.Here we precisely fabricated Au@Pt and Au@Pd core-shell catalysts on a SiO_(2) support with an identical Au core size of∼5.1 nm and a similar shell thickness of∼2 monolayers via selective atomic layer deposition.Spectroscopic characterizations were employed to compare their structural thermostability at elevated temperatures in a hydrogen reducing atmosphere.We revealed that the Au@Pt/SiO_(2) core-shell catalyst exhibited a considerably higher structural thermostability against atom inter-diffusion to alloys than that of Au@Pd/SiO_(2).Meanwhile,these two catalysts both preserved the particle size without any visible aggregation even after reduction at 550℃.Higher structural thermostability of Au@Pt/SiO_(2) core-shell catalyst might mainly stem from the distinctly higher melting point of Pt shell and their relatively smaller Au-Pt lattice mismatch.Such direct comparison of the structural thermostability of two different core-shell catalysts but with identical structures provides a valuable insight into the nature of thermodynamic behavior of bimetallic NPs at elevated temperatures.

关 键 词：双金属纳米催化剂 核壳结构 结构热稳定性 原子层沉积 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O643.36[理学—物理化学]