What is single-atom catalysis?

Single-atom catalysis is a hot new area of research. But what is it? According to an article in Nature Reviews Chemistry titled Heterogeneous single-atom catalysis …

“Single-atom catalysis, the catalysis by single-atom catalysts (SACs), has attracted considerable attention in recent years as a new frontier in the heterogeneous catalysis field. SACs have the advantages of both homogeneous catalysts (isolated active sites) and heterogeneous catalysts (stable and easy to separate), and are thus predicted to be able to bridge the homo- and heterogeneous catalysis.”

TIP #1: Google® Scholar email alert: Chunshan Song. It was the result of this alert that I found the article below. And it was this article that made me curious to find out more about single-atom catalysis.

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Preassembly Strategy To Fabricate Porous Hollow Carbonitride Spheres Inlaid with Single Cu–N3 Sites for Selective Oxidation of Benzene to Phenol
Ting Zhang†, Di Zhang†, Xinghua Han‡, Ting Dong‡, Xinwen Guo† , Chunshan Song†? , Rui Si*§, Wei Liu#, Yuefeng Liu*# , and Zhongkui Zhao*†
† State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
‡ School of Chemical Engineering and Technology, North University of China, Taiyuan 030051, P. R. China
? EMS Energy Institute, PSU-DUT Joint Center for Energy Research and Department of Energy & Mineral Engineering and Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
§ Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, P.R. China
# Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
J. Am. Chem. Soc., Article ASAP
Publication Date (Web): November 30, 2018
*sirui@sinap.ac.cn, *yuefeng.liu@dicp.ac.cn, *zkzhao@dlut.edu.cn
Abstract
Developing single-atom catalysts with porous micro-/nanostructures for high active-site accessibility is of great significance but still remains a challenge. Herein, we for the first time report a novel template-free preassembly strategy to fabricate porous hollow graphitic carbonitride spheres with single Cu atoms mounted via thermal polymerization of supramolecular preassemblies composed of a melamine–Cu complex and cyanuric acid. Atomically dispersed Cu–N3 moieties were unambiguously confirmed by spherical aberration correction electron microscopy and extended X-ray absorption fine structure spectroscopy. More importantly, this material exhibits outstanding catalytic performance for selective oxidation of benzene to phenol at room temperature, especially showing phenol selectivity (90.6 vs 64.2%) and stability much higher than those of the supported Cu nanoparticles alone, originating from the isolated unique Cu–N3 sites in the porous hollow structure. An 86% conversion of benzene, with an unexpectedly high phenol selectivity of 96.7% at 60 °C for 12 h, has been achieved, suggesting a great potential for practical applications. This work paves a new way to fabricate a variety of single-atom catalysts with diverse graphitic carbonitride architectures.
source: https://pubs.acs.org/doi/abs/10.1021/jacs.8b10703
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TIP #2: If you, like me, are new to the concept, Google® What is single-atom catalysis? for more background. Here is one of the hits from the search …

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Review Article  |  Published: 24 May 2018
Heterogeneous single-atom catalysis
Aiqin Wang, Jun Li & Tao Zhang
Nature Reviews Chemistry volume 2, pages65–81 (2018)
Abstract
Single-atom catalysis has arguably become the most active new frontier in heterogeneous catalysis. Aided by recent advances in practical synthetic methodologies, characterization techniques and computational modelling, we now have a large number of single-atom catalysts (SACs) that exhibit distinctive performances for a wide variety of chemical reactions. This Perspective summarizes recent experimental and computational efforts aimed at understanding the bonding in SACs and how this relates to catalytic performance. The examples described here illustrate the utility of SACs in a broad scope of industrially important reactions and highlight the advantages these catalysts have over those presently used. SACs have well-defined active centres, such that unique opportunities exist for the rational design of new catalysts with high activities, selectivities and stabilities. Indeed, given a certain practical application, we can often design a suitable SAC; thus, the field has developed very rapidly and afforded promising catalyst leads. Moreover, the control we have over certain SAC structures paves the way for designing base metal catalysts with the activities of noble metal catalysts. It appears that we are entering a new era of heterogeneous catalysis in which we have control over well-dispersed single-atom active sites whose properties we can readily tune.
source: https://www.nature.com/articles/s41570-018-0010-1
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