催化作用
杂原子
选择性
贵金属
金属
材料科学
化学工程
纳米颗粒
纳米技术
化学
有机化学
冶金
工程类
戒指(化学)
作者
Jae Hyung Kim,Dongyup Shin,Jaekyoung Lee,Du San Baek,Tae Joo Shin,Yong Tae Kim,Hu Young Jeong,Ja Hun Kwak,Hyungjun Kim,Sang Hoon Joo
出处
期刊:ACS Nano
[American Chemical Society]
日期:2020-01-30
卷期号:14 (2): 1990-2001
被引量:122
标识
DOI:10.1021/acsnano.9b08494
摘要
Atomically dispersed precious metal catalysts have emerged as a frontier in catalysis. However, a robust, generic synthetic strategy toward atomically dispersed catalysts is still lacking, which has limited systematic studies revealing their general catalytic trends distinct from those of conventional nanoparticle (NP)-based catalysts. Herein, we report a general synthetic strategy toward atomically dispersed precious metal catalysts, which consists of “trapping” precious metal precursors on a heteroatom-doped carbonaceous layer coated on a carbon support and “immobilizing” them with a SiO2 layer during thermal activation. Through the “trapping-and-immobilizing” method, five atomically dispersed precious metal catalysts (Os, Ru, Rh, Ir, and Pt) could be obtained and served as model catalysts for unravelling catalytic trends for the oxygen reduction reaction (ORR). Owing to their isolated geometry, the atomically dispersed precious metal catalysts generally showed higher selectivity for H2O2 production than their NP counterparts for the ORR. Among the atomically dispersed catalysts, the H2O2 selectivity was changed by the types of metals, with atomically dispersed Pt catalyst showing the highest selectivity. A combination of experimental results and density functional theory calculations revealed that the selectivity trend of atomically dispersed catalysts could be correlated to the binding energy difference between *OOH and *O species. In terms of 2 e– ORR activity, the atomically dispersed Rh catalyst showed the best activity. Our general approach to atomically dispersed precious metal catalysts may help in understanding their unique catalytic behaviors for the ORR.
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