Research on heterogeneous single-atom catalysts (SACs) has become an emerging frontier in catalysis science because of their advantages in high utilization of noble metals, precisely identified active sites, high selectivity, and tunable activity. Graphene, as a one-atom-thick two-dimensional carbon material with unique structural and electronic properties, has been reported to be a superb support for SACs. Herein, we provide an overview of recent progress in investigations of graphene-based SACs. Among the large number of publications, we will selectively focus on the stability of metal single-atoms (SAs) anchored on different sites of graphene support and the catalytic performances of graphene-based SACs for different chemical reactions, including thermocatalysis and electrocatalysis. We will summarize the fundamental understandings on the electronic structures and their intrinsic connection with catalytic properties of graphene-based SACs, and also provide a brief perspective on the future design of efficient SACs with graphene and graphene-like materials.

Theoretical Understandings of Graphene-based Metal Single-Atom Catalysts: Stability and Catalytic Performance.

Single atom catalysts (SACs) have attracted broad research interest in recent years due to their importance in various fields, such as environmental protection and energy conversion Here, we discuss the mechanisms of CO oxidation to CO2 over single Ag atoms supported on hexagonal boron-nitride sheets (Ag1/BN) through systematic van der Waals inclusive density functional theory (DFT-D) calculations The Ag adatom can be anchored onto a boron defect (VB), as suggested by the large energy barrier of 312 eV for Ag diffusion away from the VB site Three possible mechanisms (ie, Eley-Rideal, Langmuir-Hinshelwood, and termolecular Eley-Rideal) of CO oxidation over Ag1/BN are investigated Due to "CO-Promoted O2 Activation", the termolecular Eley-Rideal (TER) mechanism is the most relevant one for CO oxidation over Ag1/BN and the rate-limiting reaction barrier is only 033 eV More importantly, the first principles molecular dynamics simulations confirm that CO oxidation via the TER mechanism may easily occur at room temperature Analyses with the inclusion of temperature and entropy effects further indicate that the CO oxidation via the TER mechanism over Ag1/BN is thermodynamically favorable in a broad range of temperatures

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A promising single atom catalyst for CO oxidation: Ag on boron vacancies of h-BN sheets

Recent developments of metallic nanoparticle-graphene nanocatalysts

Exploring different reaction mechanisms for oxidation of CO over a single Pd atom incorporated nitrogen-doped graphene: A DFT study

Graphene, the reincarnation of a surface, offers new opportunities in catalytic applications, not only because of its peculiar electronic structure, but also because of the ease of modulating it. A vast number of proposals have been made to support this point, but there has been a lack of a systematic understanding of the different roles of graphene, as many other reviews published have focused on the synthesis and characterization of the various graphene-based catalysts. In this review, we surveyed the vast literature related to various theoretical proposals and experimental realizations of graphene-based catalysts to first classify and then elucidate the different roles played by graphene in solid-state heterogeneous catalysis. Owing to its one-atom thickness and zero bandgap with low density of states around Fermi level, graphene has great potential in catalysis applications. In general, graphene can function as a support for catalysts, a cover to protect catalysts, or the catalytic center itself. Understanding these functions is important in the design of catalysts in terms of how to optimize the electronic structure of the active sites for particular applications, a few case studies of which will be presented for each role.

Graphene-Based Heterogeneous Catalysis: Role of Graphene

Nitrogen coordinated silicon-doped graphene as a potential alternative metal-free catalyst for CO oxidation

The adsorption geometries of CHx species (x = 0, 1, 2, 3 and 4) on the metal embedded graphene (M–graphene) substrates and the change in electronic structure and magnetic property of systems are an...

Zigang Shen

Papers

Nitrogen coordinated silicon-doped graphene as a potential alternative metal-free catalyst for CO oxidation

The adsorption properties of CHx species on metal modified graphene