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Synthesis, Characterization and Applications of Nanoporous Functional Materials
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Synthesis, Characterization and Applications of Nanoporous Functional Materials

A special issue of Nanomaterials (ISSN 2079-4991).

Deadline for manuscript submissions: closed (20 April 2019) | Viewed by 60818

Special Issue Editors

Prof. Dr. Yusuke Yamauchi

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Guest Editor
1. School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia
2. Department of Plant & Environmental New Resources, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si 446-701, Gyeonggi-do, Korea
Interests: inorganic chemistry; materials chemistry
Special Issues, Collections and Topics in MDPI journals
Dr. Jeonghun Kim

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Guest Editor
Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
Interests: functional nanomaterials; nanoporous materials; polymers; metal-organic frameworks (MOF); carbon; metal oxide; metal; nanostructure
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Jungmok You

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Guest Editor
Department of Plant & Environmental New Resources, College of Life Sciences, Graduate School of Biotechnology, Kyung Hee University, Seoul, Republic of Korea
Interests: functional polymers; conductive polymers; nanostructured materials; hydrogels; cellulose; nanocomposites; bioelectronics; sensors; microelectrodes
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Nanoporous materials have attracted considerable attention for various applications, such as catalysts, energy storages, sensors, bioapplications, environmentally-related application, etc., due to the high surface area, functions, easy hybridization ability with other materials. In general, the nanoporous structure can be made by bottom-up or top-down approaches through the integratin of fields of material science, chemistry, nanotechnology, etc. Recently, nanoporous structures are being applied to polymers, metals, metal oxides, and carbons to improve their properties in applications. Therefore, synthesis and characterization of nanoporous materials are very important. This Special Issue explores scientific advances of nanoporous functional materials in diverse applications and includes research articles focusing on experimental studies, as well prospective discussing practical applications.

Prof. Dr. Yusuke Yamauchi
Assist. Prof. Jeonghun Kim
Prof. Dr. Jungmok You
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nanomaterials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • nanoporous
  • nanoparticles
  • functional materials
  • nanotechnology
  • carbon
  • metal oxide
  • covalent organic framework
  • catalyst
  • energy storage
  • sensor
  • bio-application

Published Papers (15 papers)

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9 pages, 1865 KiB  
Article
Fabrication of Maghemite Nanoparticles with High Surface Area
by Yulia Trushkina, Cheuk-Wai Tai and German Salazar-Alvarez
Nanomaterials 2019, 9(7), 1004; https://doi.org/10.3390/nano9071004 - 12 Jul 2019
Cited by 7 | Viewed by 2961
Abstract
Maghemite nanoparticles with high surface area were obtained from the dehydroxylation of lepidocrocite prismatic nanoparticles. The synthesis pathway from the precursor to the porous maghemite nanoparticles is inexpensive, simple and gives high surface area values for both lepidocrocite and maghemite. The obtained maghemite [...] Read more.
Maghemite nanoparticles with high surface area were obtained from the dehydroxylation of lepidocrocite prismatic nanoparticles. The synthesis pathway from the precursor to the porous maghemite nanoparticles is inexpensive, simple and gives high surface area values for both lepidocrocite and maghemite. The obtained maghemite nanoparticles contained intraparticle and interparticle pores with a surface area ca. 30 × 103 m2/mol, with pore volumes in the order of 70 cm3/mol. Both the surface area and pore volume depended on the heating rate and annealing temperature, with the highest value near the transformation temperature (180–250 °C). Following the transformation, in situ X-ray diffraction (XRD) allowed us to observe the temporal decoupling of the decomposition of lepidocrocite and the growth of maghemite. The combination of high-angle annular dark-field imaging using scanning transmission electron microscopy (HAADF-STEM) and surface adsorption isotherms is a powerful approach for the characterization of nanomaterials with high surface area and porosity. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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14 pages, 17616 KiB  
Article
A Flexible and Highly Sensitive Pressure Sensor Based on AgNWs/NRLF for Hand Motion Monitoring
by Yi Sun and Zhaoqun Du
Nanomaterials 2019, 9(7), 945; https://doi.org/10.3390/nano9070945 - 29 Jun 2019
Cited by 20 | Viewed by 4333
Abstract
Flexible, highly sensitive, easy fabricating process, low-cost pressure sensors are the trend for flexible electronic devices. Inspired by the softness, comfortable, environmental friendliness and harmless of natural latex mattress, herein, we report an agile approach of constructing a flexible 3D-architectured conductive network by [...] Read more.
Flexible, highly sensitive, easy fabricating process, low-cost pressure sensors are the trend for flexible electronic devices. Inspired by the softness, comfortable, environmental friendliness and harmless of natural latex mattress, herein, we report an agile approach of constructing a flexible 3D-architectured conductive network by dip-coating silver nanowires (AgNWs) on the natural rubber latex foam (NRLF) substrate that provide the 3D micro-network structure as the skeleton. The variation of the contact transformed into the electrical signal among the conductive three-dimensional random networks during compressive deformation is the piezoresistive effect of AgNWs/NRLF pressure sensors. The resulting AgNWs/NRLF pressure sensors exhibit desirable electrical conductivity (0.45–0.50 S/m), excellent flexibility (58.57 kPa at 80% strain), good hydrophobicity (~128° at 5th dip-coated times) and outstanding repeatability. The AgNWs/NRLF sensors can be assembled on a glove to detect hand motion sensitively such as bending, touching and holding, show potential application such as artificial skin, human prostheses and health monitoring in multifunctional pressure sensors. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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13 pages, 5104 KiB  
Article
A Novel Polymeric Adsorbent Embedded with Phase Change Materials (PCMs) Microcapsules: Synthesis and Application
by Xingang Li, Lingyu Sun, Hong Sui, Lin He, Wei Yuan and Zhenwei Han
Nanomaterials 2019, 9(5), 736; https://doi.org/10.3390/nano9050736 - 13 May 2019
Cited by 9 | Viewed by 2917
Abstract
The heat released during the industrial gas adsorption (e.g., volatile organic compounds (VOCs)) on adsorbents (e.g., activated carbon) would lead to the risks of fire and explosion in the adsorption column. Herein, a novel highly-porous Vinylbenzyl chloride-Divinylbenzene (VBC-DVB) polymeric adsorbent was synthesized with [...] Read more.
The heat released during the industrial gas adsorption (e.g., volatile organic compounds (VOCs)) on adsorbents (e.g., activated carbon) would lead to the risks of fire and explosion in the adsorption column. Herein, a novel highly-porous Vinylbenzyl chloride-Divinylbenzene (VBC-DVB) polymeric adsorbent was synthesized with embedded microcapsules (Hypercrosslinked VBC-DVB Beads (HVPM)). These microcapsules have a polydivinylbenzene-phase change materials (DVB-PCMs) core-shell structure. Paraffin wax was used as PCM filling in the spherical capsule. This microcapsules-embedded polymeric adsorbent HVPM (Φ1.5–2.0 mm) is found to possess a high specific surface area (~665 m²/g) and micropore-dominant structure. It also has heat storage capability indicated by DSC (Differential Scanning Calorimetry) analysis (11.1 J/g heat of fusion between 35.0 and 48.2 °C) for the encapsulated paraffin wax. The lab adsorption tests proved the capabilities of HVPM in adsorbing VOCs (toluene, 0.21 g/g) and controlling the temperature inside the adsorption column during the dynamic adsorption process, in which the temperature rise was lowered by 62.5%, relatively. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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13 pages, 671 KiB  
Article
A Porous Carbon with Excellent Gas Storage Properties from Waste Polystyrene
by Giorgio Gatti, Mina Errahali, Lorenzo Tei, Enzo Mangano, Stefano Brandani, Maurizio Cossi and Leonardo Marchese
Nanomaterials 2019, 9(5), 726; https://doi.org/10.3390/nano9050726 - 10 May 2019
Cited by 19 | Viewed by 4403
Abstract
In this paper, we describe the synthesis and gas adsorption properties of a porous carbonaceous material, obtained from commercial expanded polystyrene. The first step consists of the Friedel-Craft reaction of the dissolved polystyrene chains with a bridging agent to form a highly-crosslinked polymer, [...] Read more.
In this paper, we describe the synthesis and gas adsorption properties of a porous carbonaceous material, obtained from commercial expanded polystyrene. The first step consists of the Friedel-Craft reaction of the dissolved polystyrene chains with a bridging agent to form a highly-crosslinked polymer, with permanent porosity of 0.7 cm3/g; then, this polymer is treated with potassium hydroxide at a high temperature to produce a carbon material with a porous volume larger than 1.4 cm3/g and a distribution of ultramicro-, micro-, and mesopores. After characterization of the porous carbon and determination of the bulk density, the methane uptake was measured using a volumetric apparatus to pressures up to 30 bar. The equilibrium adsorption isotherm obtained is among the highest ever reported for this kind of material. The interest of this product lies both in its excellent performance and in the virtually costless starting material. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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13 pages, 3489 KiB  
Article
The Preparation and Catalytic Properties of Nanoporous Pt/CeO2 Composites with Nanorod Framework Structures
by Haiyang Wang, Dong Duan, Chen Ma, Wenyu Shi, Miaomiao Liang, Liqun Wang, Xiaoping Song, Lumei Gao and Zhanbo Sun
Nanomaterials 2019, 9(5), 683; https://doi.org/10.3390/nano9050683 - 02 May 2019
Cited by 12 | Viewed by 3647
Abstract
Pt/CeO2 catalysts with nanoporous structures were prepared by the facile dealloying of melt-spun Al92−XCe8PtX (X = 0.1; 0.3 and 0.5) ribbons followed by calcination. The phase compositions and structural parameters of the catalysts were characterized by X-ray [...] Read more.
Pt/CeO2 catalysts with nanoporous structures were prepared by the facile dealloying of melt-spun Al92−XCe8PtX (X = 0.1; 0.3 and 0.5) ribbons followed by calcination. The phase compositions and structural parameters of the catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The specific surface area and pore size distribution were characterized by N2 adsorption–desorption tests. The catalytic properties were evaluated by a three-way catalyst (TWC) measurement system. The results revealed that the dealloyed samples exhibited a nanorod framework structure. The Pt nanoparticles that formed in situ were supported and highly dispersed on the CeO2 nanorod surface and had sizes in the range of 2–5 nm. For the catalyst prepared from the melt-spun Al91.7Ce8Pt0.3 ribbons, the 50% CO conversion temperature (T50) was 91 °C, and total CO could be converted when the temperature was increased to 113 °C. An X-ray photoelectron spectroscopy (XPS) test showed that the Pt0.3/CeO2 sample had a slightly richer oxygen vacancy; and a H2 temperature-programmed reduction (H2-TPR) test demonstrated its superior adsorption ability for reduction gas and high content of active oxygen species. The experiments indicated that the catalytic performance could be retained without any attenuation after 130 h when water and CO2 were present in the reaction gas. The favorable catalytic activities were attributed to the high specific areas and small pore and Pt particle sizes as well as the strong interactions between the CeO2 and Pt nanoparticles. The Pt nanoparticles were embedded in the surface of the CeO2 nanorods, inhibiting growth. Therefore, the catalytic stability and water resistance were excellent. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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11 pages, 2558 KiB  
Article
Fabrication of Highly Conductive Porous Cellulose/PEDOT:PSS Nanocomposite Paper via Post-Treatment
by Youngsang Ko, Jeonghun Kim, Dabum Kim, Goomin Kwon, Yusuke Yamauchi and Jungmok You
Nanomaterials 2019, 9(4), 612; https://doi.org/10.3390/nano9040612 - 13 Apr 2019
Cited by 32 | Viewed by 6853
Abstract
In this paper, we report the fabrication of highly conductive poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/cellulose nanofiber (CNF) nanocomposite paper with excellent flexibility through post-treatment with an organic solvent. The post-treated PEDOT:PSS/CNF porous nanocomposite papers showed a lower sulfur content, indicating the removal of residual PSS. The [...] Read more.
In this paper, we report the fabrication of highly conductive poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/cellulose nanofiber (CNF) nanocomposite paper with excellent flexibility through post-treatment with an organic solvent. The post-treated PEDOT:PSS/CNF porous nanocomposite papers showed a lower sulfur content, indicating the removal of residual PSS. The electrical conductivity of PEDOT:PSS/CNF porous nanocomposite paper was increased from 1.05 S/cm to 123.37 S/cm and 106.6 S/cm by post-treatment with dimethyl sulfoxide (DMSO) and ethylene glycol (EG), respectively. These values are outstanding in the development of electrically conductive CNF composites. Additionally, the highly conductive nanocomposite papers showed excellent bending stability during bending tests. Cyclic voltammetry (CV) showed a Faradaic redox reaction and non-Faradaic capacitance due to the redox activity of PEDOT:PSS and large surface area, respectively. Electrochemical energy storage ability was evaluated and results showed that capacitance improved after post-treatment. We believe that the highly conductive PEDOT:PSS/CNF porous nanocomposite papers with excellent flexibility described here are potential candidates for application in porous paper electrodes, flexible energy storage devices, and bioengineering sensors. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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13 pages, 2441 KiB  
Article
Synthesis of N-Doped Micropore Carbon Quantum Dots with High Quantum Yield and Dual-Wavelength Photoluminescence Emission from Biomass for Cellular Imaging
by Xin Ren, Fang Zhang, Bingpeng Guo, Na Gao and Xiaoling Zhang
Nanomaterials 2019, 9(4), 495; https://doi.org/10.3390/nano9040495 - 01 Apr 2019
Cited by 67 | Viewed by 5350
Abstract
Pursuit of a simple, fast, and cost-effective method to prepare highly and dual-wavelength fluorescent carbon quantum dots (CQDs) is a persistent objective in recent years. Here, we fabricated N-doped micropore carbon quantum dots (NM-CQDs) with a high quantum yield and dual-wavelength photoluminescence (PL) [...] Read more.
Pursuit of a simple, fast, and cost-effective method to prepare highly and dual-wavelength fluorescent carbon quantum dots (CQDs) is a persistent objective in recent years. Here, we fabricated N-doped micropore carbon quantum dots (NM-CQDs) with a high quantum yield and dual-wavelength photoluminescence (PL) emission from sustainable biomass using a pulsed laser ablation method. Interestingly, two coexisting indigo–blue photoluminescence (PL) emissions were clearly observed, elucidating that the excited electrons transited from the intrinsic π* orbital to the surface state (SS) formed from the saturation passivation. The quantum yield (QY) and fluorescence lifetime (FL) of the obtained NM-CQDs were as high as 32.4% and 6.56 ns. Further investigations indicated that the emission behaviors of NM-CQDs were still stable and independent in various conditions such as various excitation wavelengths, salt ionic concentrations, pH values, irradiation times, and temperatures. The obtained NM-CQDs are very suitable for cellular staining images due to strong and stable PL emission and show good internalization in different cells. Therefore, we propose a new and cost-effective preparation strategy for highly fluorescent NM-CQDs with great potential in biomedical imaging and engineering. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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14 pages, 5217 KiB  
Article
Spiderweb-Like Fe-Co Prussian Blue Analogue Nanofibers as Efficient Catalyst for Bisphenol-A Degradation by Activating Peroxymonosulfate
by Hongyu Wang, Chaohai Wang, Junwen Qi, Yubo Yan, Ming Zhang, Xin Yan, Xiuyun Sun, Lianjun Wang and Jiansheng Li
Nanomaterials 2019, 9(3), 402; https://doi.org/10.3390/nano9030402 - 10 Mar 2019
Cited by 23 | Viewed by 4370
Abstract
Prussian blue and its analogues (PBA) based nanomaterials have been widely applied to removing pollutants in the recent years. However, easy aggregation and poor recycling largely limit their practical applications. In this work, spiderweb-like Fe-Co Prussian blue analogue/polyacrylonitrile (FCPBA/PAN) nanofibers were prepared by [...] Read more.
Prussian blue and its analogues (PBA) based nanomaterials have been widely applied to removing pollutants in the recent years. However, easy aggregation and poor recycling largely limit their practical applications. In this work, spiderweb-like Fe-Co Prussian blue analogue/polyacrylonitrile (FCPBA/PAN) nanofibers were prepared by electrospinning and applied to degrading bisphenol-A (BPA) by activating peroxymonosulfate (PMS). Detailed characterization demonstrated that a high loading of FCPBA (86% of FCPBA in FCPBA/PAN) was successfully fixed on the PAN nanofibers. 67% of BPA was removed within 240 min when 500 mg·L−1 PMS and 233 mg·L−1 FCPBA/PAN were introduced in 20 mg·L−1 BPA solution at initial pH of 2.8. Electron paramagnetic resonance (EPR) and radical inhibition experiments were performed to identify the possible degradation mechanism. For comparison, a low loading of FCPBA nanofibers (0.6FCPBA/PAN nanofibers, 43% of FCPBA in FCPBA/PAN) were also prepared and tested the catalytic performance. The results showed that the activity of FCPBA/PAN was much higher than 0.6FCPBA/PAN. Furthermore, a FCPBA/PAN packed column was made as a reactor to demonstrate the reusability and stability of FCPBA/PAN nanofibers, which also exhibited the bright future for the industrial application. This work makes it possible to fabricate efficient PBA nanocatalysts with excellent recyclability and promotes the application of PBA in industrial areas. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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18 pages, 5921 KiB  
Article
Tunable Synthesis of Mesoporous Carbons from Fe3O(BDC)3 for Chloramphenicol Antibiotic Remediation
by Thuan Van Tran, Duyen Thi Cam Nguyen, Hanh T. N. Le, Long Giang Bach, Dai-Viet N. Vo, Seong Soo Hong, Tri-Quang T. Phan and Trinh Duy Nguyen
Nanomaterials 2019, 9(2), 237; https://doi.org/10.3390/nano9020237 - 10 Feb 2019
Cited by 36 | Viewed by 4238
Abstract
Chloramphenicol (CAP) is commonly employed in veterinary clinics, but illegal and uncontrollable consumption can result in its potential contamination in environmental soil, and aquatic matrix, and thereby, regenerating microbial resistance, and antibiotic-resistant genes. Adsorption by efficient, and recyclable adsorbents such as mesoporous carbons [...] Read more.
Chloramphenicol (CAP) is commonly employed in veterinary clinics, but illegal and uncontrollable consumption can result in its potential contamination in environmental soil, and aquatic matrix, and thereby, regenerating microbial resistance, and antibiotic-resistant genes. Adsorption by efficient, and recyclable adsorbents such as mesoporous carbons (MPCs) is commonly regarded as a “green and sustainable” approach. Herein, the MPCs were facilely synthesized via the pyrolysis of the metal–organic framework Fe3O(BDC)3 with calcination temperatures (x °C) between 600 and 900 °C under nitrogen atmosphere. The characterization results pointed out mesoporous carbon matrix (MPC700) coating zero-valent iron particles with high surface area (~225 m2/g). Also, significant investigations including fabrication condition, CAP concentration, effect of pH, dosage, and ionic strength on the absorptive removal of CAP were systematically studied. The optimal conditions consisted of pH = 6, concentration 10 mg/L and dose 0.5 g/L for the highest chloramphenicol removal efficiency at nearly 100% after 4 h. Furthermore, the nonlinear kinetic and isotherm adsorption studies revealed the monolayer adsorption behavior of CAP onto MPC700 and Fe3O(BDC)3 materials via chemisorption, while the thermodynamic studies implied that the adsorption of CAP was a spontaneous process. Finally, adsorption mechanism including H-bonding, electrostatic attraction, π–π interaction, and metal–bridging interaction was proposed to elucidate how chloramphenicol molecules were adsorbed on the surface of materials. With excellent maximum adsorption capacity (96.3 mg/g), high stability, and good recyclability (4 cycles), the MPC700 nanocomposite could be utilized as a promising alternative for decontamination of chloramphenicol antibiotic from wastewater. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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10 pages, 2775 KiB  
Article
Nitrogen-Doped Hierarchically Porous Carbons Derived from Polybenzoxazine for Enhanced Supercapacitor Performance
by Yanhui Wang, Liyan Dong, Guiping Lai, Meng Wei, Xingbi Jiang and Lizhong Bai
Nanomaterials 2019, 9(1), 131; https://doi.org/10.3390/nano9010131 - 21 Jan 2019
Cited by 28 | Viewed by 3825
Abstract
Nitrogen-doped hierarchically porous carbons (HPCs), which are synthesized from benzoxazine resins, were successfully prepared following the processes of polymerization, carbonization, and potassium hydroxide (KOH) activation. As the key factor, the KOH activation temperature influences the pore structure and surface functionality, which are crucial [...] Read more.
Nitrogen-doped hierarchically porous carbons (HPCs), which are synthesized from benzoxazine resins, were successfully prepared following the processes of polymerization, carbonization, and potassium hydroxide (KOH) activation. As the key factor, the KOH activation temperature influences the pore structure and surface functionality, which are crucial for the excellent performance. The HPC-800 material, with the highest activation temperature (800 °C), displays a hierarchical pore structure, a high specific surface area (1812.4 m2·g−1), large total pore volume (0.98 cm3·g−1), high nitrogen content (1.27%), and remarkable electrical conductivity. It has also presented an excellent electrochemical performance of high specific capacitance of 402.4 F·g−1 at 0.1 A·g−1, excellent rate capability of 248.6 F·g−1 at 10 A·g−1, and long-term cycling stability with >99.0% capacitance retention after 500 cycles at 1 A·g−1 in 6 M KOH aqueous solution. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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9 pages, 2211 KiB  
Article
Effect of Zr Doping on the Magnetic and Phase Transition Properties of VO2 Powder
by Jing Xu, Haiying Wang, Zhihong Lu, Zhenhua Zhang, Zhaorui Zou, Ziyang Yu, Ming Cheng, Yong Liu and Rui Xiong
Nanomaterials 2019, 9(1), 113; https://doi.org/10.3390/nano9010113 - 18 Jan 2019
Cited by 8 | Viewed by 4078
Abstract
In this work, V1−xZrxO2 powder (x = 0, 0.01, 0.02, 0.04) was synthesized by two step hydrothermal method. The micro-topography, magnetic and phase transition properties have been investigated using various measurement techniques. All prepared V1−xZrx [...] Read more.
In this work, V1−xZrxO2 powder (x = 0, 0.01, 0.02, 0.04) was synthesized by two step hydrothermal method. The micro-topography, magnetic and phase transition properties have been investigated using various measurement techniques. All prepared V1−xZrxO2 powder samples exhibit monoclinic structure at room temperature. With the Zr4+ ions doping concentration increased, the shapes of VO2 particles change from spherical to rectangular slice. Besides, the saturation magnetic moment of the samples decrease with the increase of doped Zr4+ ions concentration, while their phase transition temperature increase gradually with Zr ions doping at a rate of around 2 °C/at% on average. We investigated the Zr doping effects on V-V dimers and confirmed the role of V-V dimers in phase transition. We speculate that more V-V dimers form with Zr doping by magnetic measurements, which result in the monoclinic phase of Zr-doped VO2 sample is more stable than rutile phase. Therefore the phase transition temperature is elevated by Zr doping in our experiment. We further consider that the VO2 phase transition should be ascribed to Peierls transition caused by the changing of V-V dimers. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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12 pages, 5361 KiB  
Article
Preparation and Properties of SiBCO Aerogel and Its Composites
by Xiafei Li, Junzong Feng, Jie Yin, Yonggang Jiang and Jian Feng
Nanomaterials 2019, 9(1), 40; https://doi.org/10.3390/nano9010040 - 29 Dec 2018
Cited by 6 | Viewed by 3067
Abstract
To obtain new high-temperature resistant composites that can meet the requirements of aircraft development for thermal insulation and mechanical properties, SiBCO aerogel composites were prepared by sol-gel, supercritical drying and high-temperature pyrolysis with trimethyl borate (TMB) or phenylboronic acid (PBA) as the boron [...] Read more.
To obtain new high-temperature resistant composites that can meet the requirements of aircraft development for thermal insulation and mechanical properties, SiBCO aerogel composites were prepared by sol-gel, supercritical drying and high-temperature pyrolysis with trimethyl borate (TMB) or phenylboronic acid (PBA) as the boron source and mullite fiber as reinforcement. The structure and composition of the SiBCO aerogel and its composites were characterized with SEM, FT-IR, ICP and nitrogen adsorption tests. The specific surface area of the SiBCO aerogel is 293.22 m2/g, and the pore size is concentrated in the range of 10–150 nm. The mechanical properties, the thermal insulation properties and the temperature resistance were also studied. Due to the introduction of boron, the temperature resistance of SiBCO aerogel composites is improved greatly, and the service temperature of composites reached 1773 K. When n (TMB)/n (TEOS) = 1/1, the temperature resistance of the composites is the best. After heating in air at 1773 K for 30 min, the shrinkage of SiBCO aerogel composites is only 2.45%, and the thermal conductivity of the composites is 0.138 W/(m·K) at 1773 K. In addition, the type and amount of catalyst also have certain effects on the mechanical properties and temperature resistance of the composites. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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9 pages, 2136 KiB  
Letter
Synthesis of Mesoporous TiO2-B Nanobelts with Highly Crystalized Walls toward Efficient H2 Evolution
by Ping Li, Qing Cao, Dehua Zheng, Abdulmohsen Ali Alshehri, Yousef Gamaan Alghamidi, Khalid Ahmed Alzahrani, Minjun Kim, Jie Hou, Linfei Lai, Yusuke Yamauchi, Yusuke Ide, Yoshio Bando, Jeonghun Kim, Victor Malgras and Jianjian Lin
Nanomaterials 2019, 9(7), 919; https://doi.org/10.3390/nano9070919 - 26 Jun 2019
Cited by 10 | Viewed by 3289
Abstract
Mesoporous TiO2 is attracting increasing interest due to properties suiting a broad range of photocatalytic applications. Here we report the facile synthesis of mesoporous crystalline TiO2-B nanobelts possessing a surface area as high as 80.9 m2 g−1 and [...] Read more.
Mesoporous TiO2 is attracting increasing interest due to properties suiting a broad range of photocatalytic applications. Here we report the facile synthesis of mesoporous crystalline TiO2-B nanobelts possessing a surface area as high as 80.9 m2 g−1 and uniformly-sized pores of 6–8 nm. Firstly, P25 powders are dissolved in NaOH solution under hydrothermal conditions, forming sodium titanate (Na2Ti3O7) intermediate precursor phase. Then, H2Ti3O7 is successfully obtained by ion exchange through acid washing from Na2Ti3O7 via an alkaline hydrothermal treatment. After calcination at 450 °C, the H2Ti3O7 is converted to a TiO2-B phase. At 600 °C, another anatase phase coexists with TiO2-B, which completely converts into anatase when annealed at 750 °C. Mesoporous TiO2-B nanobelts obtained after annealing at 450 °C are uniform with up to a few micrometers in length, 50–120 nm in width, and 5–15 nm in thickness. The resulting mesoporous TiO2-B nanobelts exhibit efficient H2 evolution capability, which is almost three times that of anatase TiO2 nanobelts. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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12 pages, 3847 KiB  
Letter
Cyano-Bridged Cu-Ni Coordination Polymer Nanoflakes and Their Thermal Conversion to Mixed Cu-Ni Oxides
by Alowasheeir Azhar, Christine Young, Yusuf Valentino Kaneti, Yusuke Yamauchi, Ahmad Yacine Badjah, Mu Naushad, Mohamed Habila, Saikh Wabaidur, Zeid A. Alothman and Jeonghun Kim
Nanomaterials 2018, 8(12), 968; https://doi.org/10.3390/nano8120968 - 23 Nov 2018
Cited by 6 | Viewed by 3233
Abstract
Herein, we demonstrate the bottom-up synthesis of 2D cyano-bridged Cu-Ni coordination polymer (CP) nanoflakes through a controlled crystallization process and their conversion to Cu-Ni mixed oxides via a thermal treatment in air. The chelating effect of citrate anions effectively prevents the rapid coordination [...] Read more.
Herein, we demonstrate the bottom-up synthesis of 2D cyano-bridged Cu-Ni coordination polymer (CP) nanoflakes through a controlled crystallization process and their conversion to Cu-Ni mixed oxides via a thermal treatment in air. The chelating effect of citrate anions effectively prevents the rapid coordination reaction between Cu2+ and K2[Ni(CN)4], resulting in the deceleration of the crystallization process of CPs. Specifically, with addition of trisodium citrate dehydrate, the number of nuclei formed at the early stage of the reaction is decreased. Less nuclei undergo a crystal growth by interacting with [Ni(CN)4]2−, leading to the formation of larger Cu-Ni CP nanoflakes. Following heat treatment in air, the -CN- groups present within the CP nanoflakes are removed and nanoporous Cu-Ni mixed oxide nanoflakes are generated. When tested as an electrode material for supercapacitors using a three-electrode system, the optimum Cu-Ni mixed oxide sample shows a maximum specific capacitance of 158 F g−1 at a current density of 1 A g−1. It is expected that the proposed method will be useful for the preparation of other types of 2D and 3D CPs as precursors for the creation of various nanoporous metal oxides. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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10 pages, 1431 KiB  
Letter
Micelle-Assisted Strategy for the Direct Synthesis of Large-Sized Mesoporous Platinum Catalysts by Vapor Infiltration of a Reducing Agent
by Yunqi Li, Yuwei Liu, Yusuke Yamauchi, Yusuf Valentino Kaneti, Saad M. Alsheri, Tansir Ahamad, Norah Alhokbany, Jeonghun Kim, Katsuhiko Ariga, Ning Wu and Jun Xu
Nanomaterials 2018, 8(10), 841; https://doi.org/10.3390/nano8100841 - 16 Oct 2018
Cited by 3 | Viewed by 3345
Abstract
Stable polymeric micelles have been demonstrated to serve as suitable templates for creating mesoporous metals. Herein, we report the utilization of a core-shell-corona type triblock copolymer of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) and H2PtCl6·H2O to synthesize [...] Read more.
Stable polymeric micelles have been demonstrated to serve as suitable templates for creating mesoporous metals. Herein, we report the utilization of a core-shell-corona type triblock copolymer of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) and H2PtCl6·H2O to synthesize large-sized mesoporous Pt particles. After formation of micelles with metal ions, the reduction process has been carried out by vapor infiltration of a reducing agent, 4-(Dimethylamino)benzaldehyde. Following the removal of the pore-directing agent under the optimized temperature, mesoporous Pt particles with an average pore size of 15 nm and surface area of 12.6 m2·g−1 are achieved. More importantly, the resulting mesoporous Pt particles exhibit superior electrocatalytic activity compared to commercially available Pt black. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Applications of Nanoporous Functional Materials)
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