Murata Kazumasa, Eleeda Eleen, Ohyama Junya, Yamamoto Yuta, Arai Shigeo, Satsuma Atsushi
Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan.
Phys Chem Chem Phys. 2019 Aug 21;21(33):18128-18137. doi: 10.1039/c9cp03943k.
The active sites of Pd/Al2O3 catalysts for CO oxidations were identified by investigating the dependence of CO oxidation activities on the surface structure and morphology of Pd nanoparticles. The maximum catalytic activity was obtained for Pd particles approximately 2 nm in particle size. We performed structural analyses on the Pd surface through infrared (IR) spectroscopy of the adsorbed CO molecules. A positive correlation was obtained between catalytic activity and the fraction of linear CO adsorbed on Pd corner sites and Pd(111) facets, indicating that these sites are highly active for CO oxidation. X-ray absorption fine structure (XAFS) and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) measurements demonstrated that Pd nanoparticles less than 2 nm in particle size with amorphous-like structures and Pd particles with large, well-ordered structures favor the formation of a high fraction of corner sites and Pd(111) facets, respectively.
通过研究CO氧化活性对Pd纳米颗粒表面结构和形态的依赖性，确定了用于CO氧化的Pd/Al₂O₃催化剂的活性位点。粒径约为2 nm的Pd颗粒具有最大催化活性。我们通过吸附的CO分子的红外（IR）光谱对Pd表面进行了结构分析。催化活性与吸附在Pd角位和Pd(111)晶面上的线性CO的比例之间存在正相关，表明这些位点对CO氧化具有高活性。X射线吸收精细结构（XAFS）和球差校正扫描透射电子显微镜（Cs-STEM）测量表明，粒径小于2 nm的具有类非晶结构的Pd纳米颗粒和具有大的、有序结构的Pd颗粒分别有利于形成高比例的角位和Pd(111)晶面。
