化学
催化作用
格式化
纳米团簇
近程
纳米颗粒
无机化学
纳米材料基催化剂
光化学
粒径
多相催化
甲烷化
金属
过渡金属
漫反射红外傅里叶变换
一氧化碳
物理化学
化学工程
光催化
有机化学
工程类
作者
Kexin Ma,Weiqi Liao,Wen Shi,Fangkai Xu,Yan Zhou,Cen Tang,Ji-Qing Lu,Wenjie Shen,Zhenhua Zhang
标识
DOI:10.1016/j.jcat.2022.01.023
摘要
Supported metal catalysts are the most widely used in industrial processes and the metal particle size plays a crucial factor in determining the catalytic performance. Herein, CeO2-supported Pd catalysts with different Pd size regimes ranging from single atoms, to nanoclusters (1–2 nm), and to nanoparticles (>2 nm) were used for both CO oxidation and preferential oxidation of CO in H2 (CO-PROX). Compared to Pd nanoclusters and nanoparticles, CeO2-supported single Pd atoms (PdSA/CeO2) are the most intrinsically active in CO oxidation, with an apparent activation energy of ca. 40 kJ mol−1. Results of kinetic investigations and in situ diffuse reflectance infrared Fourier transformed spectroscopy demonstrate the CO oxidation proceeding through a Langmuir-Hinshelwood mechanism with the decomposition of formate species acting dominantly as the rate-determining step. The CO reaction rate is exclusively promoted on PdSA/CeO2 catalysts for the CO-PROX reaction, which could be ascribed to a stronger H-spillover effect on isolated Pd sites to produce bridged-OH on CeO2 surface, simultaneously facilitating the consumptions of bicarbonate and formate species. There results greatly deepen the fundamental understanding of the Pd size regimes over Pd/CeO2 catalysts for the oxidation of CO.
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