Graphene-supported single-atom catalysts and applications in electrocatalysis

Abstract

Supported metal nanostructures are the most extensively studied heterogeneous catalysts, benefiting from easy separation, regeneration and affordable cost. The size of the supported metal species is one of the decisive factors in determining the activity of heterogeneous catalysts. Particularly, the unsaturated coordination environment of metal atoms preferably act as the active centers, minimizing these metal species can significantly boost the specific activity of every single metal atom. Single-atom catalysts/catalysis (SACs), containing isolated metals atomically dispersed on or coordinated with the surface of a support material, represent the ultimate utilization of supported metals and maximize metal usage efficiency. Graphene, a two-dimensional star material, exhibiting extraordinary physical and chemical properties, has been approved as an excellent platform for constructing SACs. When atomically dispersed metal atoms are strongly anchored on the graphene surface, featuring ultra-high surface area and excellent electronic properties, SACs offer a great potential to significantly innovate the conventional heterogeneous catalysis, especially in the field of electrocatalysis. In this review, a detailed discussion of graphene-supported SACs, including preparation approaches, characterization techniques and applications on typical electrocatalytic reactions is provided. The advantages and unique features of graphene-supported SACs as efficient electrocatalysts and the upcoming challenges for improving their performance and further practical applications are also highlighted.

Rational Design of Electrocatalysts Comprising Single-Atom-Modified Covalent Organic Frameworks for the N2 Reduction Reaction: A First-Principles Study

“…In addition, the metal stabilization energies increase with increasing d-electron number when the metal atoms with the same CN are compared. This result is consistent with those in previous papers related to single-metal active centers. , However, several previous studies showed that the interaction between pristine graphene and single-metal atoms is relatively weak. − Thus, the stabilization energies were also compared with the cohesive energy calculated using bulk metals, as also listed in Table . The calculated values revealed that the metal atoms with M–N 4 structures are more stable than those in bulk metal atoms, whereas the stabilized energies for metal atoms with M–N 2 and M–N 3 structures are more positive than the corresponding cohesive energies.…”

Rational Design of Single‐Atom Site Electrocatalysts: From Theoretical Understandings to Practical Applications

“…Some compounds, such as metals, metal oxides, metal chlorides/carbides/ nitrides/sulfides, layered double hydroxides (LDHs), and other modified carbon materials, are used as the supports to stabilize the single atoms. [19][20][21] In addition, enormous preparation strategies of stable and high-efficiency electrocatalysts are also presented, such as the impregnation and coprecipitation strategy, spatial confinement strategy, coordination site construction strategy, defect/vacant design strategy, electrochemical method, atomic layer deposition (ALD) method, synthesizing SACs from bulk metals or metal oxide powers, ball-milling method, and so on.Atomically dispersed metal-based electrocatalysts have attracted increasing attention due to their nearly 100% atomic utilization and excellent catalytic performance. However, current fundamental comprehension and summaries to reveal the underlying relationship between single-atom site electrocatalysts (SACs) and corresponding catalytic application are rarely reported.…”

“…Some compounds, such as metals, metal oxides, metal chlorides/carbides/ nitrides/sulfides, layered double hydroxides (LDHs), and other modified carbon materials, are used as the supports to stabilize the single atoms. [19][20][21] In addition, enormous preparation strategies of stable and high-efficiency electrocatalysts are also presented, such as the impregnation and coprecipitation strategy, spatial confinement strategy, coordination site construction strategy, defect/vacant design strategy, electrochemical method, atomic layer deposition (ALD) method, synthesizing SACs from bulk metals or metal oxide powers, ball-milling method, and so on.…”

Defect Engineering of Graphene Hybrid Catalysts for Oxygen Reduction Reactions

“…可算出电解液中双氧水浓度 [29] 。 2 结果与讨论 石墨烯是一种零带隙的二维材料, 可通过原子 掺杂、化学修饰等方法打开石墨烯的带隙 [31][32][33] , 从 而提升其电化学性能。拉曼光谱中, D 峰(1350 cm -1 ) 与 G 峰(1580 cm -1 )的强度比(I D /I G )可以表征石墨烯 中缺陷密度 [34] ORR 的电子转移数可以通过 K-L 法计算。 氧还 原反应中电流的关系可用式(4)表示：…”