Specific surface area of hierarchical graphitic substrates suitable for multi-functional applications

Barney, Ian T.; Lennaerts, Dennis S.R.; Higgins, Steven R.; Mukhopadhyay, Sharmila M.

doi:10.1016/j.matlet.2012.08.042

Cited by 15 publications

(5 citation statements)

References 13 publications

(17 reference statements)

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“…In this article, we aim to suggest an alternate scheme for enhancing the energy density of EC devices. The basis for a concomitant enhancement in the energy density, while maintaining power capability, hinges on the use of hierarchical assemblies constituted from porous structures where the internal pore area is covered with closely spaced nanostructures [13][14][15][16][17]. The rationale for the use of such assemblies is to incorporate both macroscale pores (e.g., of ~ 100 m as in RVC) -which enable the storage of substantial electrolyte volumes that would contribute through redox reactions to the energy density, while the nanostructures may be used to provide a large geometric area and capacitance in addition to enhancing the rate of Faradaic processes which is typically limited by species diffusion [18,19].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical charge storage in hierarchical carbon manifolds

Narayanan

Vijwani

Mukhopadhyay

et al. 2016

Carbon

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The use of hierarchical assemblies constituted from macroporous structures (e.g., reticulated vitreous carbon, RVC) where the internal pore area is covered with closely spaced nanostructures (e.g., carbon nanotubes, CNT) is proposed for substantially enhancing the energy density of electrochemical capacitors, while maintaining large charge/discharge rates. While the macroscale pores enable storage of substantial electrolyte volumes that would contribute through redox reactions to the energy density, the closely spaced nanostructures provide a large geometric area and capacitance in addition to enabling rate independent Faradaic charge storage via thin layer electrochemistry (TLE). A fifty fold increase in the double layer capacitance, in addition to increased Faradaic charge densitywith potential for orders of magnitude improvement, was observed for the RVC-CNT electrodes, in comparison to the bare RVC foam electrode. It was seen that the hierarchical assembly enables the contribution from ~ 94% of the net volume of the wetted RVC-CNT electrode for active Faradaic charge storage.

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Section: Introductionmentioning

confidence: 99%

Electrochemical charge storage in hierarchical carbon manifolds

Narayanan

Vijwani

Mukhopadhyay

et al. 2016

Carbon

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“…It was shown that attachment of the CNT carpet could easily increase the specific surface area (SSA) of these materials by several orders of magnitude, controllable by processing parameters and deposition times. Microstructural studies of CNT distribution and morphology was combined with physical measurements to make geometrical estimates of SSA, which matched very well with gas adsorption studies using Brunauer–Emmett–Teller (BET) analyses [ 152 ]. It was also seen that the entire CNT surface was available for adsorption of molecular species from the surrounding environment, as tested for by Methylene Blue adsorption in water.…”

Section: Supports For Pd Nanocatalysts Developed Specifically For Wat...mentioning

confidence: 99%

Advances in Matrix-Supported Palladium Nanocatalysts for Water Treatment

2022

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Advanced catalysts are crucial for a wide range of chemical, pharmaceutical, energy, and environmental applications. They can reduce energy barriers and increase reaction rates for desirable transformations, making many critical large-scale processes feasible, eco-friendly, energy-efficient, and affordable. Advances in nanotechnology have ushered in a new era for heterogeneous catalysis. Nanoscale catalytic materials are known to surpass their conventional macro-sized counterparts in performance and precision, owing it to their ultra-high surface activities and unique size-dependent quantum properties. In water treatment, nanocatalysts can offer significant promise for novel and ecofriendly pollutant degradation technologies that can be tailored for customer-specific needs. In particular, nano-palladium catalysts have shown promise in degrading larger molecules, making them attractive for mitigating emerging contaminants. However, the applicability of nanomaterials, including nanocatalysts, in practical deployable and ecofriendly devices, is severely limited due to their easy proliferation into the service environment, which raises concerns of toxicity, material retrieval, reusability, and related cost and safety issues. To overcome this limitation, matrix-supported hybrid nanostructures, where nanocatalysts are integrated with other solids for stability and durability, can be employed. The interaction between the support and nanocatalysts becomes important in these materials and needs to be well investigated to better understand their physical, chemical, and catalytic behavior. This review paper presents an overview of recent studies on matrix-supported Pd-nanocatalysts and highlights some of the novel emerging concepts. The focus is on suitable approaches to integrate nanocatalysts in water treatment applications to mitigate emerging contaminants including halogenated molecules. The state-of-the-art supports for palladium nanocatalysts that can be deployed in water treatment systems are reviewed. In addition, research opportunities are emphasized to design robust, reusable, and ecofriendly nanocatalyst architecture.

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“…Macro-porous graphitic materials can serve as substrates for holding nano-sized carbon objects [88]. Porous monoliths obtained by SPS from diatomite powders are recommended for water purification and waste water treatment [62].…”

Section: Potential Applications Of Porous Materials Obtained By Spsmentioning

confidence: 99%

Fabrication of Porous Materials by Spark Plasma Sintering: A Review

2019

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Spark plasma sintering (SPS), a sintering method that uses the action of pulsed direct current and pressure, has received a lot of attention due to its capability of exerting control over the microstructure of the sintered material and flexibility in terms of the heating rate and heating mode. Historically, SPS was developed in search of ways to preserve a fine-grained structure of the sintered material while eliminating porosity and reaching a high relative density. These goals have, therefore, been pursued in the majority of studies on the behavior of materials during SPS. Recently, the potential of SPS for the fabrication of porous materials has been recognized. This article is the first review to focus on the achievements in this area. The major approaches to the formation of porous materials by SPS are described: partial densification of powders (under low pressures, in pressureless sintering processes or at low temperatures), sintering of hollow particles/spheres, sintering of porous particles, and sintering with removable space holders or pore formers. In the case of conductive materials processed by SPS using the first approach, the formation of inter-particle contacts may be associated with local melting and non-conventional mechanisms of mass transfer. Studies of the morphology and microstructure of the inter-particle contacts as well as modeling of the processes occurring at the inter-particle contacts help gain insights into the physics of the initial stage of SPS. For pre-consolidated specimens, an SPS device can be used as a furnace to heat the materials at a high rate, which can also be beneficial for controlling the formation of porous structures. In sintering with space holders, SPS processing allows controlling the structure of the pore walls. In this article, using the literature data and our own research results, we have discussed the formation and structure of porous metals, intermetallics, ceramics, and carbon materials obtained by SPS.

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Specific surface area of hierarchical graphitic substrates suitable for multi-functional applications

Cited by 15 publications

References 13 publications

Electrochemical charge storage in hierarchical carbon manifolds

Electrochemical charge storage in hierarchical carbon manifolds

Advances in Matrix-Supported Palladium Nanocatalysts for Water Treatment

Fabrication of Porous Materials by Spark Plasma Sintering: A Review

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