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Yusuke Yamauchi - One of the best experts on this subject based on the ideXlab platform.
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fabrication of nanoporous carbon materials with Hard and soft Templating approaches a review
Journal of Nanoscience and Nanotechnology, 2019Co-Authors: Victor Malgras, Katsuhiko Ariga, Jing Tang, Jie Wang, Jeonghun Kim, Nagy L Torad, Saikat Dutta, Shahriar A Hossain, Yusuke YamauchiAbstract:Hard- and soft-Templating approaches are one of potential strategies for the fabrication of functional nanoporous carbon materials with desired morphologies and properties. Enormous efforts have been paid for understanding the synthetic mechanisms that strongly influence the materials design and applications. All of these investigations are crucial to encourage the application of Hard- and soft-Templating approaches for the precise synthesis of nanoporous carbon materials. In this review, we mainly summarize significant works employing different synthetic methods for making carbon materials with various pore sizes and functionalities. The content of the review article contains: (i) Hard-Templating synthesis of microporous carbon from zeolites; (ii) Hard-Templating synthesis of mesoporous carbon from mesoporous silica; (iii) Hard-Templating synthesis of macroporous carbon; and (iv) Soft-Templating synthesis of mesoporous carbon. This review aims to provide a detailed glimpse of Hard- and soft-Templating approaches for future development of functional nanoporous carbon materials.
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Hard-templated preparation of mesoporous cobalt phosphide as an oxygen evolution electrocatalyst
Electrochemistry Communications, 2019Co-Authors: Peng Mei, Yusuke Yamauchi, Yusuf Valentino Kaneti, Malay Pramanik, Amanullah Fatehmulla, Abdullah M. Adhafiri, W. Aslam Farooq, Yoshio Bando, Muhammad J. A. Shiddiky, Jianjian LinAbstract:Herein, we examine the application of mesoporous cobalt phosphide (meso-CoP) prepared by a Hard-Templating method as a novel non-precious electrocatalyst for the oxygen evolution reaction (OER). The obtained meso-CoP exhibits a relatively low overpotential (0.30 V at 10 mA cm), a decent Tafel slope (81 mV dec), and good long-term stability, performing better than its bulk counterpart and many state-of-the-art Co-based OER electrocatalysts. The high electrocatalytic performance of the meso-CoP toward OER is attributed to two key factors: (1) a large accessible active surface which endows the meso-CoP with numerous active sites for water oxidation; (2) a well-organized mesoporous structure which expedites the electron/ion transfer and mass transport, thereby significantly enhancing the OER kinetics. This work will provide guidance for designing inexpensive high-performance electrocatalysts with exquisite mesostructures for potential applications in commercial water-splitting technology.
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nanoarchitectures for metal organic framework derived nanoporous carbons toward supercapacitor applications
Accounts of Chemical Research, 2016Co-Authors: Rahul R Salunkhe, Yusuf Valentino Kaneti, Yusuke YamauchiAbstract:ConspectusThe future advances of supercapacitors depend on the development of novel carbon materials with optimized porous structures, high surface area, high conductivity, and high electrochemical stability. Traditionally, nanoporous carbons (NPCs) have been prepared by a variety of methods, such as templated synthesis, carbonization of polymer precursors, physical and chemical activation, etc. Inorganic solid materials such as mesoporous silica and zeolites have been successfully utilized as templates to prepare NPCs. However, the Hard-Templating methods typically involve several synthetic steps, such as preparation of the original templates, formation of carbon frameworks, and removal of the original templates. Therefore, these methods are not favorable for large-scale production.Metal–organic frameworks (MOFs) with high surface areas and large pore volumes have been studied over the years, and recently, enormous efforts have been made to utilize MOFs for electrochemical applications. However, their lo...
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Hard-Templating synthesis of macroporous platinum microballs (MPtM)
Materials Letters, 2016Co-Authors: Hiroaki Shirai, Yu-yuan Huang, Tetsu Yonezawa, Tomoharu Tokunaga, Wei-chen Chang, Saad M. Alshehri, Bo Jiang, Yusuke YamauchiAbstract:Abstract Platinum (Pt) is widely applied for electrochemical catalysis, thus creating porosity in Pt-based materials would enhance their catalytic efficacy. This study demonstrates a new route to synthesize a Pt material with macropores and spherical morphology by the combination of evaporation induced self-assembly of a Hard template (i.e., silica nanoparticles) and infiltration/reduction of Pt species in micro-emulsion systems. The synthesized macroporous Pt microballs (denoted as MPtM) are characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and it is found that MPtM exhibits uniform macropores (diameter of 300 nm) and Pt crystalline framework, which would be potential for enhanced catalytic reactions.
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electrochemical synthesis of one dimensional mesoporous pt nanorods using the assembly of surfactant micelles in confined space
Angewandte Chemie, 2013Co-Authors: Cuiling Li, Yusuke Yamauchi, Takaaki SatoAbstract:of metals affords electrocatalystsshowing a superior performance because of their highporosity, large area per unit volume, and excellent activity–structure relationship. Therefore, the successful synthesis of1D mesoporous Pt motifs can be expected to be a newdirection in the fabrication of superior electrocatalysts. Thetraditional Hard-Templating method, which is widely used tosynthesize mesoporous carbon materials,
Dmitry Volodkin - One of the best experts on this subject based on the ideXlab platform.
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self assembled mucin containing microcarriers via Hard Templating on caco3 crystals
Micromachines, 2018Co-Authors: N G Balabushevich, Dmitry Volodkin, Ekaterina A Sholina, E V Mikhalchik, L Y Filatova, Anna S VikulinaAbstract:Porous vaterite crystals of CaCO3 are extensively used for the fabrication of self-assembled polymer-based microparticles (capsules, beads, etc.) utilized for drug delivery and controlled release. The nature of the polymer used plays a crucial role and discovery of new perspective biopolymers is essential to assemble microparticles with desired characteristics, such as biocompatibility, drug loading efficiency/capacity, release rate, and stability. Glycoprotein mucin is tested here as a good candidate to assemble the microparticles because of high charge due to sialic acids, mucoadhesive properties, and a tendency to self-assemble, forming gels. Mucin loading into the crystals via co-synthesis is twice as effective as via adsorption into preformed crystals. Desialylated mucin has weaker binding to the crystals most probably due to electrostatic interactions between sialic acids and calcium ions on the crystal surface. Improved loading of low-molecular-weight inhibitor aprotinin into the mucin-containing crystals is demonstrated. Multilayer capsules (mucin/protamine)3 have been made by the layer-by-layer self-assembly. Interestingly, the deposition of single mucin layers (mucin/water)3 has also been proven, however, the capsules were unstable, most probably due to additional (to hydrogen bonding) electrostatic interactions in the case of the two polymers used. Finally, approaches to load biologically-active compounds (BACs) into the mucin-containing microparticles are discussed.
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controlling the vaterite caco3 crystal pores design of tailor made polymer based microcapsules by Hard Templating
Langmuir, 2016Co-Authors: Natalia Feoktistova, Anna S Vikulina, Juergen Rose, Vladimir Z Prokopovic, Andre G Skirtach, Dmitry VolodkinAbstract:The spherical vaterite CaCO3 microcrystals are nowadays widely used as sacrificial templates for fabrication of various microcarriers made of biopolymers (e.g., proteins, nucleic acids, enzymes) due to porous structure and mild template elimination conditions. Here, we demonstrated for the first time that polymer microcarriers with tuned internal nanoarchitecture can be designed by employing the CaCO3 crystals of controlled porosity. The layer-by-layer deposition has been utilized to assemble shell-like (hollow) and matrix-like (filled) polymer capsules due to restricted and free polymer diffusion through the crystal pores, respectively. The crystal pore size in the range of few tens of nanometers can be adjusted without any additives by variation of the crystal preparation temperature in the range 7–45 °C. The temperature-mediated growth mechanism is explained by the Ostwald ripening of nanocrystallites forming the crystal secondary structure. Various techniques including SEM, AFM, CLSM, Raman microscopy...
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Colloids of pure proteins by Hard Templating
Colloid and Polymer Science, 2014Co-Authors: Dmitry VolodkinAbstract:Colloidal particles from pure proteins are favorable over composite colloids (usually polymer-based) for applications in drug delivery and biocatalysis. This is due to degradation issue and protein unfolding. Hard Templating based on porous CaCO_3 cores has been recently adopted for fabrication of pure protein colloids. In comparison to conventional techniques, the Templating offers (i) a control over particles size and (ii) mild preparation conditions without any additives, shear forces, and exposure to high temperature or gas-water interface. In this review, the current achievements in CaCO_3-based Templating of protein colloids are given. The focus is on physicochemical and material properties of the colloids such as stability, mechanical properties, and internal structure. These properties are considered as a function of pH, ionic strength, and protein denaturation degree. Understanding of these basic aspects gives an option to formulate the protein colloids by Hard Templating achieving desired particle properties that is crucially important for future applications.
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one step formulation of protein microparticles with tailored properties Hard Templating at soft conditions
Advanced Functional Materials, 2012Co-Authors: Dmitry Volodkin, Helmuth Möhwald, Stephan Schmidt, Paulo A L Fernandes, N I Larionova, Gleb B Sukhorukov, Claus Duschl, R Von KlitzingAbstract:Formulation of therapeutic proteins into particulate forms is a main strategy for site-specific and prolonged protein delivery as well as for protection against degradation. Precise control over protein particle size, dispersity, purity, as well as mild preparation conditions and minimal processing steps are highly desirable. It is, however, Hard to fit all these criteria with conventional preparation techniques. Here a one-step Hard-Templating synthesis of microparticles composed of functional, non-denatured protein is reported. The method is based on filling porous CaCO3 microtemplates with the protein near to its isoelectric point (pI) followed by pH- or EDTA-mediated dissolution of the tempplates. In principle, a wide variety of proteins can be converted into microparticles using this approach. The main requirement is an overlap of the protein insolubility and a template solubility for a certain parameter (here pH or EDTA). Here the formulation of insulin particles is studied in detail and it is shown that particles consisting of high molecular weight protein (catalase) can also be prepared. In this context, the synthesis of CaCO3 templates with controlled size, the mechanism of the protein microparticle formation and mechanical properties of the microparticles are discussed. For the first time, the fabrication of mesoporous monodispersed CaCO3 microtemplates with identical porocity but tuned diameter from 3 to 20 μm is demonstrated. The protein particle diameter can be adjusted by choosing the appropriate template size that is critical for successful pulmonary delivery of insulin. As a first step towards insulin delivery, the in vitro release of insulin at physiological conditions is studied.
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Synthesis of porous PEG microgels using CaCO3 microspheres as Hard templates.
Macromolecular rapid communications, 2012Co-Authors: Muriel Behra, Dmitry Volodkin, Stephan Schmidt, Jürgen Hartmann, Laura HartmannAbstract:Porous poly(ethylene glycol) (PEG) microgels of both 17.6 and 8.3 μ m in diameter are synthesized via Hard Templating with calcium carbonate (CaCO 3 ) microparticles. The synthesis is performed in three steps: loading of PEG macromonomers into CaCO 3 microparticles, crosslinking via photopolymerization, and removal of the CaCO 3 template under acidic conditions. The resulting porous PEG microgels are inverse replicates of their templates as indicated by light microscopy, cryo-scanning electron microscopy (cryoSEM), and permeability studies. Thus this process allows for the straightforward and highly reproducible synthesis of porous hydrogel particles of two different diameters and porosities that show great potential as carriers for drugs or nanomaterials.
Markus Antonietti - One of the best experts on this subject based on the ideXlab platform.
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carbon aerogels and monoliths control of porosity and nanoarchitecture via sol gel routes
Chemistry of Materials, 2014Co-Authors: Markus Antonietti, Nina Fechler, Timpatrick FellingerAbstract:The synthesis of carbon aerogels by sol–gel like processes, i.e., Hard Templating, phase demixing, hydrothermal carbonization techniques, as well as by ionothermal syntheses are reviewed. In all these techniques, we start with a liquid reaction solution, where—controlled by experimental parameters and structure-directing additives—a porous carbon material with high conductivity, high pore volume, and high specific surface area is obtained. Many of these synthesis approaches give the resulting material in simple, rather sustainable processes, and the structures can be employed directly after isolation without further activation processes. The article will discuss also some applications, such as battery and electrode materials as well as catalyst supports.
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enhanced carbon dioxide adsorption by a mesoporous poly ionic liquid
ACS Macro Letters, 2012Co-Authors: Antje Wilke, Jiayin Yuan, Markus Antonietti, Jens WeberAbstract:The synthesis of a mesoporous poly(ionic liquid) network via a Hard-Templating pathway is presented. Structure analysis was carried out using gas adsorption, small-angle X-ray scattering, and electron microscopy. The mesoporous poly(ionic liquid) showed a significantly faster CO2 adsorption than its nonporous counterpart. We found the adsorption is accompanied by strong interactions, which are also reflected in a high CO2 over N2 selectivity.
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efficient metal free oxygen reduction in alkaline medium on high surface area mesoporous nitrogen doped carbons made from ionic liquids and nucleobases
Journal of the American Chemical Society, 2011Co-Authors: We Yang, Timpatrick Fellinge, Markus AntoniettiAbstract:Mesoporous nitrogen-doped carbon materials with high surface areas up to 1500 m2 g−1 were conveniently made by the carbonization of nucleobases dissolved in an all-organic ionic liquid (1-ethyl-3-methylimidazolium dicyanamide). Using Hard Templating with silica nanoparticles, this process yields high-surface-area nitrogen-doped carbon materials with nitrogen contents as high as 12 wt %, narrow mesopore size distribution of ca. 12 nm diameter, and local graphitic carbon structure. It is demonstrated that the resulting nitrogen-doped carbons show very high catalytic activity, even in the metal-free case in the oxygen reduction reaction (ORR) for fuel cells. Specifically, the as-prepared materials exhibit a low onset voltage for ORR in alkaline medium and a high methanol tolerance, compared with those of commercial 20 wt % Pt/C catalyst. We regard this as a first step toward an all-sustainable fuel cell, avoiding noble metals.
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high surface area nanoporous boron carbon nitrides for hydrogen storage
Advanced Functional Materials, 2010Co-Authors: David Portehault, Stefan Kaskel, Cristina Giordano, Christel Gervais, Irena Senkovska, Clement Sanchez, Markus AntoniettiAbstract:Nano- and mesoporous boron carbon nitrides with very high surface areas up to 1560 m2 g−1 are obtained by pyrolysis of a graphitic carbon nitride mpg-C3N4 infiltrated with a borane complex. This reactive Hard-Templating approach provides easy composition and texture tuning by temperature adjustment between 800 and 1400 °C. The process yields BxCyNzOvHw materials as direct copies of the initial template with controlled compositions of 0.15 ≤ x ≤ 0.36, 0.10 ≤ y ≤ 0.12, 0.14 ≤ z ≤ 0.32, and 0.11 ≤ v ≤ 0.28. The nano and mesoporosities can also be tuned in order to provide hierarchical materials with specific surface areas ranging from 610 to 1560 m2 g−1. Such high values, coupled with resistance against air oxidation up to 700 °C, suggest potential materials for gas storage and as catalyst supports. Indeed, it is demonstrated that these compounds exhibit high and tunable H2 uptakes from 0.55 to 1.07 wt.% at 77 K and 1 bar, thus guiding further search of materials for hydrogen storage.
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mesoporous poly benzimidazole networks via solvent mediated Templating of Hard spheres
Macromolecules, 2007Co-Authors: Jens Weber, Markus Antonietti, Arne ThomasAbstract:Mesoporous Poly(benzimidazole) with well-defined porosity and pore diameter of 11 nm was synthesized via a Hard Templating approach using silica nanoparticles as template. The effect of the template concentration as well as the influence of the cross-linking density on the resulting pore structure was investigated. The samples were characterized by small-angle X-ray scattering and nitrogen sorption, revealing a linear increase of the porosity and surface area with increasing content of the template up to a critical concentration. Exceeding this concentration leads to a breakdown of some pores due to the emerging high interfacial energy. The effect of the cross-linking density was shown to be nonlinear. Samples with more than 20 mol % cross-linker revealed perfect replication of the template, while a lower cross-linking density leads to a breakdown of some pores.
Rui Ding - One of the best experts on this subject based on the ideXlab platform.
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Correction: A facile Hard-Templating synthesis of mesoporous spinel CoFe2O4 nanostructures as promising electrocatalysts for the H2O2 reduction reaction
RSC Advances, 2015Co-Authors: Rui Ding, Mingjun Jia, Hongyu WangAbstract:Correction for ‘A facile Hard-Templating synthesis of mesoporous spinel CoFe2O4 nanostructures as promising electrocatalysts for the H2O2 reduction reaction’ by Rui Ding et al., RSC Adv., 2014, 4, 1754–1760.
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a facile Hard Templating synthesis of mesoporous spinel cofe2o4 nanostructures as promising electrocatalysts for the h2o2 reduction reaction
RSC Advances, 2014Co-Authors: Rui Ding, Mingjun Jia, Hongyu WangAbstract:Mesoporous spinel cobalt ferrite (CoFe2O4) nanostructures were synthesized via a facile Al2O3-assisted Hard-Templating (HT) strategy. Their physicochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectra (SEM-EDS), X-ray photoelectron spectra (XPS) and nitrogen sorption measurements. Their electrocatalytic performances towards H2O2 reduction reaction (HRR) were investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) tests. The obtained CoFe2O4 materials exhibit a superior mesoporous nanostructure with a particle size of around 20 nm, a specific surface area (SSA) of 140.6 m2 g−1 and a mesopore volume of 0.2410 cm3 g−1, which favor their desirable electrocatalytic activity. A current density of 123 mA cm−2 at −0.39 V (vs. Hg/HgO) in 3 M NaOH and 0.5 M H2O2 electrolytes was delivered for HRR. Moreover, the CoFe2O4 electrode exhibits a good stability for the catalytic reaction, showing the promising applications for H2O2-based alkaline fuel cells (AFCs).
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hierarchical porous nico2o4 nanomaterials with excellent cycling behavior for electrochemical capacitors via a Hard Templating route
Journal of Applied Electrochemistry, 2012Co-Authors: Rui Ding, Mingjun Jia, Hongyu WangAbstract:Hierarchical porous nickel cobaltite (NiCo2O4) nanomaterials were synthesized via a Hard-Templating route. The obtained materials consist of nanostructured cubic NiCo2O4 spinels and a spot of cubic NiO nanoparticles, and the materials display a typical hierarchical porous structure. The NiCo2O4 electrode displays quasireversible dynamics characteristics, mainly Faradaic capacitance behavior and capacitance relaxation feature. The NiCo2O4 electrode exhibits an excellent long cycling behavior with no capacitance decays during 5,000 cycles at a current density of 2 A g−1 in 1 M KOH electrolytes, and the NiCo2O4 electrode exhibits both high power and energy performances even after 5,000 cycles with respective value of 1,758 W kg−1 and 8.3 W h kg−1 in 1 M KOH electrolytes, indicating that the NiCo2O4 nanomaterials are promising candidates for electrochemical capacitors.
Hongyu Wang - One of the best experts on this subject based on the ideXlab platform.
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Correction: A facile Hard-Templating synthesis of mesoporous spinel CoFe2O4 nanostructures as promising electrocatalysts for the H2O2 reduction reaction
RSC Advances, 2015Co-Authors: Rui Ding, Mingjun Jia, Hongyu WangAbstract:Correction for ‘A facile Hard-Templating synthesis of mesoporous spinel CoFe2O4 nanostructures as promising electrocatalysts for the H2O2 reduction reaction’ by Rui Ding et al., RSC Adv., 2014, 4, 1754–1760.
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a facile Hard Templating synthesis of mesoporous spinel cofe2o4 nanostructures as promising electrocatalysts for the h2o2 reduction reaction
RSC Advances, 2014Co-Authors: Rui Ding, Mingjun Jia, Hongyu WangAbstract:Mesoporous spinel cobalt ferrite (CoFe2O4) nanostructures were synthesized via a facile Al2O3-assisted Hard-Templating (HT) strategy. Their physicochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectra (SEM-EDS), X-ray photoelectron spectra (XPS) and nitrogen sorption measurements. Their electrocatalytic performances towards H2O2 reduction reaction (HRR) were investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) tests. The obtained CoFe2O4 materials exhibit a superior mesoporous nanostructure with a particle size of around 20 nm, a specific surface area (SSA) of 140.6 m2 g−1 and a mesopore volume of 0.2410 cm3 g−1, which favor their desirable electrocatalytic activity. A current density of 123 mA cm−2 at −0.39 V (vs. Hg/HgO) in 3 M NaOH and 0.5 M H2O2 electrolytes was delivered for HRR. Moreover, the CoFe2O4 electrode exhibits a good stability for the catalytic reaction, showing the promising applications for H2O2-based alkaline fuel cells (AFCs).
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hierarchical porous nico2o4 nanomaterials with excellent cycling behavior for electrochemical capacitors via a Hard Templating route
Journal of Applied Electrochemistry, 2012Co-Authors: Rui Ding, Mingjun Jia, Hongyu WangAbstract:Hierarchical porous nickel cobaltite (NiCo2O4) nanomaterials were synthesized via a Hard-Templating route. The obtained materials consist of nanostructured cubic NiCo2O4 spinels and a spot of cubic NiO nanoparticles, and the materials display a typical hierarchical porous structure. The NiCo2O4 electrode displays quasireversible dynamics characteristics, mainly Faradaic capacitance behavior and capacitance relaxation feature. The NiCo2O4 electrode exhibits an excellent long cycling behavior with no capacitance decays during 5,000 cycles at a current density of 2 A g−1 in 1 M KOH electrolytes, and the NiCo2O4 electrode exhibits both high power and energy performances even after 5,000 cycles with respective value of 1,758 W kg−1 and 8.3 W h kg−1 in 1 M KOH electrolytes, indicating that the NiCo2O4 nanomaterials are promising candidates for electrochemical capacitors.
