With the fabrication of single atom catalysts (SACs) as a new concept, researches on catalysts have deep into smaller scale, which can make it available to dissect complex heterogeneous catalysis on atomic lever, simultaneously provide vast opportunities for applications in industrial catalysis because of their predominant performances. Based on the previous achievements, the main components of this research are as follows: the performance characteristics of SACs are summarized, the preparation, characterizations and theoretical approaches about SACs are introduced, the research developments of applications in CO oxidization, selective hydrogenation and photoelectrocatalysis reaction, etc. are illustrated, the influences of the exceptive electronic structure of SACs on catalytic performance and reaction mechanism are analyzed, the breakthroughs and the shortages of SACs system are pointed out. All these discussions contribute to the profound understanding on principles of SACs, improvement of both theoretical and experimental researches, and furthermore put forward suggestions and prospective for expanding its application range and achieving industrial applications.

Contents
1 Introduction
2 Fabrication and properties of SACs
2.1 Selection of substrates
2.2 Preparation methods
2.3 Catalytic characteristics
3 Structural characterization of SACs
3.1 Characterization methods
3.2 Structual characterization
4 Theoretical methods
4.1 Configuration prediction
4.2 Exploration of reaction mechanism
5 Application of SACs
5.1 Oxidation reaction
5.2 Hydrogenation reaction
5.3 Photoelectrocatalysis reaction
5.4 Other reactions
6 Conclusion