Chemical reactions confined within carbon nanotubes

Miners, Scott A.; Rance, Graham A.; Khlobystov, Andrei N.

doi:10.1039/c6cs00090h

Cited by 193 publications

(164 citation statements)

References 139 publications

(324 reference statements)

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“…It is noted that NCs prepared by modifying CNT with FeS 2 particles have attracted a great deal of consideration as a catalytic material due to its chemical, structural, physical, and optical properties ,. The formation energy of oxygen vacancies and metal interstitials in FeS 2 NCs is very low and thus the defects are formed easily compared to other materials making the material suitable for catalyzing an electrochemical process . In the present study, FeS 2 ‐CNT NCs was synthesized and immobilized on a GCE to check the possibility of catalyzing the oxidation of 4‐AP molecules such that p‐quinone can be synthesized in the aqueous medium.…”

Section: Introductionmentioning

confidence: 96%

Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS₂/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

et al. 2019

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FeS2/carbon nanotube (CNT) nanocomposites were synthesized and immobilized on the surface of a glassy carbon electrode (GCE) in order to investigate the electrocatalytic conversion of 4‐aminophenol (4‐AP) into p‐quinone in an aqueous medium. The reformed electronic properties (in terms of lowering of band‐gap energy and charge‐transfer resistance), as well as improved surface area, result in an enhanced redox reaction of 4‐AP in the presence of FeS2‐CNT NCs compared to that with FeS2 alone. The 4‐AP molecules undergo coupled two‐proton and two‐electron transfer quasi‐reversible redox reactions with a symmetry factor of 0.55 and standard rate constant (k°) of 0.8 cm s−1. Here, quinone imine is generated as an intermediate which is later converted into quinone in an irreversible hydrolysis reaction. The best catalytic performance can be obtained at the pH value of 7.0.

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Section: Introductionmentioning

confidence: 96%

Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS₂/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

et al. 2019

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“…To solve this problem, confined synthesis method, as an extension of the template‐assisted synthesis method, has been proposed. Confinement, a concept coming from catalysis and surface science, has been utilized for the restriction of nanoparticles or molecules in a nanospace or on the surface to improve their catalytic properties 15–20. In the field of materials science and engineering, the concept of confinement has also been developed for the controlled synthesis of nanomaterials.…”

Section: Introductionmentioning

confidence: 99%

Confined Synthesis of 2D Nanostructured Materials toward Electrocatalysis

Zhang

Cheng

et al. 2019

Advanced Energy Materials

155

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2D nanostructured materials have shown great application prospects in energy conversion, owing to their unique structural features and fascinating physicochemical properties. Developing efficient approaches for the synthesis of well‐defined 2D nanostructured materials with controllable composition and morphology is critical. The emerging concept, confined synthesis, has been regarded as a promising strategy to design and synthesize novel 2D nanostructured materials. This review mainly summarizes the recent advances in confined synthesis of 2D nanostructured materials by using layered materials as host matrices (also denoted as “nanoreactors”). By virtue of the space‐ and surface‐confinement effects of these layered hosts, various well‐organized 2D nanostructured materials, including 2D metals, 2D metal compounds, 2D carbon materials, 2D polymers, 2D metal‐organic frameworks (MOFs) and covalent‐organic frameworks (COFs), as well as 2D carbon nitrides are successfully synthesized. The wide employment of these 2D materials in electrocatalytic applications (e.g., electrochemical oxygen/hydrogen evolution reactions, small molecule oxidation, and oxygen reduction reaction) is presented and discussed. In the final section, challenges and prospects in 2D confined synthesis from the viewpoint of designing new materials and exploring practical applications are commented, which would push this fast‐evolving field a step further toward greater success in both fundamental studies and ultimate industrialization.

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“…Theoretical investigations reveal that the spatially confined environment increases the molecular orbital energy and changes activity of the confined molecules, which have been recognized as the nest effect and quantum confinement effect (15, 16). In past decades, some experimental studies have demonstrated that carbon nanotubes (CNTs) strongly affect catalytic reactions occurring inside the nanotubes (7,17,18), and confined catalysis in 1D nanocavities has been theoretically addressed by studying molecule adsorption on metal clusters encapsulated in CNTs (19). As illustrated in Fig.…”

mentioning

confidence: 99%

Confined catalysis under two-dimensional materials

Xiao

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

237

189

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Confined microenvironments formed in heterogeneous catalysts have recently been recognized as equally important as catalytically active sites. Understanding the fundamentals of confined catalysis has become an important topic in heterogeneous catalysis. Well-defined 2D space between a catalyst surface and a 2D material overlayer provides an ideal microenvironment to explore the confined catalysis experimentally and theoretically. Using density functional theory calculations, we reveal that adsorption of atoms and molecules on a Pt(111) surface always has been weakened under monolayer graphene, which is attributed to the geometric constraint and confinement field in the 2D space between the graphene overlayer and the Pt(111) surface. A similar result has been found on Pt(110) and Pt(100) surfaces covered with graphene. The microenvironment created by coating a catalyst surface with 2D material overlayer can be used to modulate surface reactivity, which has been illustrated by optimizing oxygen reduction reaction activity on Pt(111) covered by various 2D materials. We demonstrate a concept of confined catalysis under 2D cover based on a weak van der Waals interaction between 2D material overlayers and underlying catalyst surfaces.confined catalysis | two-dimensional materials | density functional theory | oxygen reduction reaction | graphene I n heterogeneous catalysis, active sites have long been regarded as one of the most important concepts (1-3), and, recently, the heterogeneous catalysis community has started to recognize that microenvironment around the active site is equally important (4-9). The confined microenvironment on a heterogeneous catalyst can help to stabilize active sites and modulate chemistry at the sites, which has a significant effect on catalytic performance, similar to the role of spheroproteins in an enzyme (10). Hence, understanding fundamentals of confined catalysis has become an important topic in heterogeneous catalysis (11,12).Reactions in zero-dimensional (0D) nanocavities of microporous and mesoporous materials such as zeolites and metal−organic frameworks (MOFs) have shown enhanced catalytic performance (6,9,(13)(14)(15). Theoretical investigations reveal that the spatially confined environment increases the molecular orbital energy and changes activity of the confined molecules, which have been recognized as the nest effect and quantum confinement effect (15, 16). In past decades, some experimental studies have demonstrated that carbon nanotubes (CNTs) strongly affect catalytic reactions occurring inside the nanotubes (7,17,18), and confined catalysis in 1D nanocavities has been theoretically addressed by studying molecule adsorption on metal clusters encapsulated in CNTs (19). As illustrated in Fig. 1, both 0D nanocavities in zeolites and 1D nanocavities in CNTs are spatially confined in three dimensions and two dimensions, respectively, in which simple and well-defined model systems are not feasible for both theoretical and experimental studies. Moreover, structural and composit...

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Chemical reactions confined within carbon nanotubes

Cited by 193 publications

References 139 publications

Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS₂/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS₂/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

Confined Synthesis of 2D Nanostructured Materials toward Electrocatalysis

Confined catalysis under two-dimensional materials

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Chemical reactions confined within carbon nanotubes

Cited by 193 publications

References 139 publications

Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS2/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS2/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

Confined Synthesis of 2D Nanostructured Materials toward Electrocatalysis

Confined catalysis under two-dimensional materials

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Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS₂/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

Electrocatalytic Oxidation of 4‐Aminophenol Molecules at the Surface of an FeS₂/Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium