催化作用
纳米棒
X射线光电子能谱
铈
材料科学
氧化态
氧化铈
离解(化学)
兴奋剂
金属
无机化学
扩展X射线吸收精细结构
Atom(片上系统)
物理化学
化学
纳米技术
化学工程
吸收光谱法
嵌入式系统
计算机科学
工程类
物理
冶金
量子力学
生物化学
光电子学
作者
Yanbo Deng,Pengfei Tian,Shijie Liu,Huaqiang He,Yuan Wang,Like Ouyang,Shaojun Yuan
标识
DOI:10.1016/j.jhazmat.2021.127793
摘要
Single-atom noble metal catalysts have been widely studied for catalytic oxidation of CO. Regulating the coordination environment of single metal atom site is an effective strategy to improve the intrinsic catalytic activity of single atom catalyst. In this work, single atom Pd catalyst supported on Pr-doped CeO2 nanorods was prepared, and the performance and nature of Pr-coordinated atomic Pd site in CO catalytic oxidation are systematically investigated. The structure characterization using AC-HAADF-STEM, EXAFS, XRD and Raman spectroscopy demonstrate the formation of single atom Pd site and abundant surface oxygen vacancies on the surface of Pr-doped CeO2 nanorod. With the combination of the XPS characterization and DFT calculations, the oxidation state of Pd on Pr-doped CeO2 nanorod is determined lower than that on CeO2 nanorod. The turnover frequency of CO oxidation is markedly increased from 8.4 × 10-3 to 31.9 × 10-3 s with Pr-doping at 130 ºC and GHSV of 70,000 h-1. Combined with kinetic studies, DRIFT and DFT calculations, the doped-Pr atoms reduced the formation energy of oxygen vacancies and generate more oxygen vacancies around the atomically dispersed Pd sites on the surface of cerium oxide, which reduces the dissociation energy of oxygen, thereby accelerating the reaction rate of CO oxidation.
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