One‐dimensional nanomaterial supported metal single‐atom electrocatalysts: Synthesis, characterization, and applications

Zhao, Haoyue; Zhang, Chuanxiong; Han, Li; Fang, J.

doi:10.1002/nano.202100083

Cited by 13 publications

(17 citation statements)

References 152 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is easy to form nanoparticles due to agglomeration without stronger interactions between surface metal atoms and carriers. When defect sites of a carrier trap single atoms, a single atomic structure can remain thermodynamically stabilized, which has been confirmed by many recent studies [188,299]. Defective carrier design is vital for controlling the atomic structure of the metal.…”

Section: Stabilizationmentioning

confidence: 84%

Advanced Strategies for Stabilizing Single-Atom Catalysts for Energy Storage and Conversion

Guo

Yang

et al. 2022

Electrochem. Energy Rev.

View full text Add to dashboard Cite

Well-defined atomically dispersed metal catalysts (or single-atom catalysts) have been widely studied to fundamentally understand their catalytic mechanisms, improve the catalytic efficiency, increase the abundance of active components, enhance the catalyst utilization, and develop cost-effective catalysts to effectively reduce the usage of noble metals. Such single-atom catalysts have relatively higher selectivity and catalytic activity with maximum atom utilization due to their unique characteristics of high metal dispersion and a low-coordination environment. However, freestanding single atoms are thermodynamically unstable, such that during synthesis and catalytic reactions, they inevitably tend to agglomerate to reduce the system energy associated with their large surface areas. Therefore, developing innovative strategies to stabilize single-atom catalysts, including mass-separated soft landing, one-pot pyrolysis, co-precipitation, impregnation, atomic layer deposition, and organometallic complexation, is critically needed. Many types of supporting materials, including polymers, have been commonly used to stabilize single atoms in these fabrication techniques. Herein, we review the stabilization strategies of single-atom catalyst, including different synthesis methods, specific metals and carriers, specific catalytic reactions, and their advantages and disadvantages. In particular, this review focuses on the application of polymers in the synthesis and stabilization of single-atom catalysts, including their functions as carriers for metal single atoms, synthetic templates, encapsulation agents, and protection agents during the fabrication process. The technical challenges that are currently faced by single-atom catalysts are summarized, and perspectives related to future research directions including catalytic mechanisms, enhancement of the catalyst loading content, and large-scale implementation are proposed to realize their practical applications. Graphical Abstract Single-atom catalysts are characterized by high metal dispersibility, weak coordination environments, high catalytic activity and selectivity, and the highest atom utilization. However, due to the free energy of the large surface area, individual atoms are usually unstable and are prone to agglomeration during synthesis and catalytic reactions. Therefore, researchers have developed innovative strategies, such as soft sedimentation, one-pot pyrolysis, coprecipitation, impregnation, step reduction, atomic layer precipitation, and organometallic complexation, to stabilize single-atom catalysts in practical applications. This article summarizes the stabilization strategies for single-atom catalysts from the aspects of their synthesis methods, metal and support types, catalytic reaction types, and its advantages and disadvantages. The focus is on the application of polymers in the preparation and stabilization of single-atom catalysts, including metal single-atom carriers, synthetic templates, encapsulation agents, and the role of polymers as protection agents in the manufacturing process. The main feature of polymers and polymer-derived materials is that they usually contain abundant heteroatoms, such as N, that possess lone-pair electrons. These lone-pair electrons can anchor the single metal atom through strong coordination interactions. The coordination environment of the lone-pair electrons can facilitate the formation of single-atom catalysts because they can enlarge the average distance of a single precursor adsorbed on the polymer matrix. Polymers with nitrogen groups are favorable candidates for dispersing active single atoms by weakening the tendency of metal aggregation and redistributing the charge densities around single atoms to enhance the catalytic performance. This review provides a summary and analysis of the current technical challenges faced by single-atom catalysts and future research directions, such as the catalytic mechanism of single-atom catalysts, sufficiently high loading, and large-scale implementation.

show abstract

Section: Stabilizationmentioning

confidence: 84%

Advanced Strategies for Stabilizing Single-Atom Catalysts for Energy Storage and Conversion

Guo

Yang

et al. 2022

Electrochem. Energy Rev.

View full text Add to dashboard Cite

show abstract

“…The strategy typically involves mixing metal-containing precursors and doped materials (N, P, S sources, which can provide additional defective sites and coordination groups to stabilize the metal atoms) and support materials followed by high-temperature thermal conversion. [40] This method is often used for the doping modification and carbonization of 1D materials. For example, Abbas et al [50] designed and prepared homogeneous 1D CNTs doped with Fe, N, P and O atoms by carbonizing the novel PFC nanotubes.…”

Section: Hybrid Pyrolysis Methodsmentioning

confidence: 99%

A Review of One‐Dimensional Nanomaterials as Electrode Materials for Oxygen Reduction Reaction Electrocatalysis

et al. 2022

View full text Add to dashboard Cite

In fuel cells, the generally low oxygen reduction reactions (ORR) rate at the cathode is a major factor limiting the overall performance of fuel cell, so the development of high‐performance, stable and inexpensive ORR electrocatalysts is a major researching direction. Nano‐electrocatalysts, especially one‐dimensional (1D) electrocatalysts, exhibit good catalytic behavior in fuel cell reactions due to their unique anisotropic structure, large specific surface area, high elasticity and excellent stability. To date, many advanced 1D electrocatalysts have been reported for optimizing the cathode ORR of fuel cells. Therefore, a comprehensive review of the structural design of 1D nano‐electrocatalysts and a systematic analysis of their enhanced performance still need further summarized and concluded. In this review, we firstly introduce the main synthetic methods of 1D electrocatalysts, and then discuss the recent advances and advantages of different structured 1D electrocatalysts involving nanofibers, nanotubes, nanorods, nanochains, nanowires, nanobelts, nanoneedles, nanowhiskers, and coaxial nanocables. In addition, we also introduce 1D electrocatalysts while highlighting advanced strategies and preparation methods for these different structured 1D electrocatalysts to improve ORR performance. Finally, we prospect the future development of 1D ORR electrocatalysts.

show abstract

“…The hydro/solvothermal, and template‐assisted pyrolysis methods can be commonly used to prepare the 1D structured carbon‐supported SACs. [ 35 ] For example, Fe single atoms anchored into 1D nanotube electrocatalyst was achieved via simple carbonization with tellurium nanowires as hard templates, N‐containing small molecule as carbon source and inorganic metal salt as metal precursors (Figure 2d–f). 1D porous CNTs with N‐coordinated Fe single sites exhibited excellent ORR electrocatalytic activity.…”

Section: Macro‐environment Engineering Carbon‐supported Sacsmentioning

confidence: 99%

Macro/Micro‐Environment Regulating Carbon‐Supported Single‐Atom Catalysts for Hydrogen/Oxygen Conversion Reactions

Huo

Shen

Cao

et al. 2022

Small

View full text Add to dashboard Cite

Electrochemical storage and conversion systems, such as water electrolyzers, proton exchange membrane (PEM) fuel cells and metal-air batteries, have drawn extensive attention in the last decades. Hydrogen and oxygen conversion reactions, including hydrogen evolution reaction (HER), hydrogen oxidation reaction (HOR), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR), are important reactions in the above-mentioned systems. Specifically, water electrolyzer with HER and OER at cathode and anode, respectively, can transform electricity into clean energy (H 2 ); [4] the fuel cells can convert chemical energy into electricity with HOR at anode and ORR at the cathode; [5] the electrochemical ORR/OER is the pair of inverse reactions during the discharge/charge processes in rechargeable metal-air batteries. [6] Currently, precious metal-based electrocatalysts are still required to drive these electrochemical reactions for high performance. However, the high price and low distribution of precious metals block further commercial applications. [7] Therefore, the exploration of precious metals with low loading and/or nonprecious metal-based catalysts without the compromise of their catalytic activity has been the core of developing renewable energy.In recent years, nanosized catalysts, that is, nanoparticles, quantum dots, and clusters, have been developed rapidly for various electrochemical conversion reactions, such as HER, Single-atom catalysts (SACs) have attracted tremendous research interest due to their unique atomic structure, maximized atom utilization, and remarkable catalytic performance. Among the SACs, the carbon-supported SACs have been widely investigated due to their easily controlled properties of the carbon substrates, such as the tunable morphologies, ordered porosity, and abundant anchoring sites. The electrochemical performance of carbonsupported SACs is highly related to the morphological structure of carbon substrates (macro-environment) and the local coordination environments of center metals (micro-environment). This review aims to provide a comprehensive summary on the macro/micro-environment regulating carbonsupported SACs for highly efficient hydrogen/oxygen conversion reactions. The authors first summarize the macro-environment engineering strategies of carbon-supported SACs with altered specific surface areas and porous properties of the carbon substrates, facilitating the mass diffusion kinetics and structural stability. Then the micro-environment engineering strategies of carbon-supported SACs are discussed with the regulated atomic structure and electronic structure of metal centers, boosting the catalytic performance. Insights into the correlation between the co-boosted effect from the macro/ micro-environments and catalytic activity for hydrogen/oxygen conversion reactions are summarized and discussed. Finally, the challenges and perspectives are addressed in building highly efficient carbon-supported SACs for practical applications.

show abstract

One‐dimensional nanomaterial supported metal single‐atom electrocatalysts: Synthesis, characterization, and applications

Cited by 13 publications

References 152 publications

Advanced Strategies for Stabilizing Single-Atom Catalysts for Energy Storage and Conversion

Advanced Strategies for Stabilizing Single-Atom Catalysts for Energy Storage and Conversion

A Review of One‐Dimensional Nanomaterials as Electrode Materials for Oxygen Reduction Reaction Electrocatalysis

Macro/Micro‐Environment Regulating Carbon‐Supported Single‐Atom Catalysts for Hydrogen/Oxygen Conversion Reactions

Contact Info

Product

Resources

About