Dual Light- and pH-Responsive Composite of Polyazo-Derivative Grafted Cellulose Nanocrystals

As a type of functional group, azo-derivatives are commonly used to synthesize responsive materials. Cellulose nanocrystals (CNCs), prepared by acid hydrolysis of cotton, were dewatered and reacted with 2-bromoisobuturyl bromide to form a macro-initiator, which grafted 6-[4-(4-methoxyphenyl-azo) phenoxy] hexyl methacrylate (MMAZO) via atom transfer radical polymerization. The successful grafting was supported by Fourier transform infrared spectroscopy (FT-IR) and Solid magnetic resonance carbon spectrum (MAS 13C-NMR). The morphology and surface composition of the poly{6-[4-(4-methoxyphenylazo) phenoxy] hexyl methacrylate} (PMMAZO)-grafted CNCs were confirmed with Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The grafting rate on the macro-initiator of CNCs was over 870%, and the polydispersities of branched polymers were narrow. The crystal structure of CNCs did not change after grafting, as determined by X-ray diffraction (XRD). The polymer PMMAZO improved the thermal stability of cellulose nanocrystals, as shown by thermogravimetry analysis (TGA). Then the PMMAZO-grafted CNCs were mixed with polyurethane and casted to form a composite film. The film showed a significant light and pH response, which may be suitable for visual acid-alkali measurement and reversible optical storage.

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Carbon Supported Pt+Os Catalysts for Methanol Oxidation

Zeitschrift für Naturforschung B ◽

10.1515/znb-2002-0211 ◽

2002 ◽

Vol 57 (2) ◽

pp. 193-201 ◽

Cited By ~ 8

Author(s):

Gülsün Gökağaç ◽

Brendan J. Kennedy

Keyword(s):

Methanol Oxidation ◽

Photoelectron Spectroscopy ◽

Surface Composition ◽

Carbon Support ◽

Methanol Oxidation Reaction ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Metal Metal ◽

Metal Support

11% Pt/C, 10% Pt + 1%Os/C, 9% Pt + 2%Os/C, 8% Pt + 3%Os/C, 7% Pt + 4%Os/C, 6% Pt + 5%Os/C and 5%Pt + 6% Os/C catalysts have been prepared for methanol oxidation reaction. Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cyclic voltammetry have been used to understand the nature of the species present in these catalysts. 7% Pt + 4% Os/C was the most active catalyst, while 8% Pt + 3% Os/C was the least active one. It is found that the metal particle size and distribution on the carbon support, the surface composition and the oxidation states of the metal particles, the metal-metal and metal support interactions are important parameters to define the activity of the catalyst.

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Preparation, Characterization, and Performance Analysis of S-Doped Bi2MoO6 Nanosheets

Nanomaterials ◽

10.3390/nano9091341 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1341 ◽

Cited By ~ 1

Author(s):

Ruiqi Wang ◽

Duanyang Li ◽

Hailong Wang ◽

Chenglun Liu ◽

Longjun Xu

Keyword(s):

Photoelectron Spectroscopy ◽

Degradation Rate ◽

X Ray Diffraction ◽

Photo Degradation ◽

X Ray ◽

Transmission Electron ◽

Ft Ir ◽

And Performance ◽

Adsorption Desorption ◽

Excellent Stability

S-doped Bi2MoO6 nanosheets were successfully synthesized by a simple hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), elemental mapping spectroscopy, photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectra (UV-vis DRS). The photo-electrochemical performance of the samples was investigated via an electrochemical workstation. The S-doped Bi2MoO6 nanosheets exhibited enhanced photocatalytic activity under visible light irradiation. The photo-degradation rate of Rhodamine B (RhB) by S-doped Bi2MoO6 (1 wt%) reached 97% after 60 min, which was higher than that of the pure Bi2MoO6 and other S-doped products. The degradation rate of the recovered S-doped Bi2MoO6 (1 wt%) was still nearly 90% in the third cycle, indicating an excellent stability of the catalyst. The radical-capture experiments confirmed that superoxide radicals (·O2−) and holes (h+) were the main active substances in the photocatalytic degradation of RhB by S-doped Bi2MoO6.

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Green preparation of carbon dots for Hg2+ detection and cell imaging

Materials Express ◽

10.1166/mex.2020.1843 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1777-1787

Author(s):

Yadian Xie ◽

Shanshan Wang ◽

Ning Fu ◽

Yan Yang ◽

Xingliang Liu ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Carbon Dots ◽

High Sensitivity ◽

Amorphous Structure ◽

X Ray Diffraction ◽

X Ray ◽

Carbon And Nitrogen ◽

Transmission Electron ◽

Sensitivity And Selectivity ◽

Ft Ir

Carbon dots (CDs) also nitrogen-doped CDs (N-CDs) were produced by green hydrothermal synthesis using Pea and ethanediamine as the carbon and nitrogen source, separately. Transmission electron microscopy (TEM) images displayed that the prepared CDs and N-CDs were well dispersed, had a spherical morphology. X-ray diffraction (XRD) figures of CDs and N-CDs presented a graphitic amorphous structure. Fourier transform infrared spectroscopy (FT-IR) verified that CDs and N-CDs carried many different hydrophilic groups (for example hydroxyl, carboxyl/carbonyl, amide, amino groups) on the surface, X-ray photoelectron spectroscopy (XPS) together verified this result. However, the optical properties and fluorescence quantum yield for N-CDs were obviously superior to those of CDs. Furthermore, the prepared N-CDs displayed outstanding advantages including low toxicity, satisfactory biocompatibility, and excellent chemical stability. More prominently, the prepared N-CDs could detect Hg2+ ions with high sensitivity and selectivity in both water samples and HeLa cells.

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The Construction of the Heterostructural Bi2O3/g-C3N4 Composites with an Enhanced Photocatalytic Activity

NANO ◽

10.1142/s1793292018500637 ◽

2018 ◽

Vol 13 (06) ◽

pp. 1850063 ◽

Cited By ~ 4

Author(s):

Jinhua Zhang ◽

Huiyue Qian ◽

Wencheng Liu ◽

Hao Chen ◽

Yang Qu ◽

...

Keyword(s):

Photocatalytic Activity ◽

Photoelectron Spectroscopy ◽

Photogenerated Electron ◽

X Ray Diffraction ◽

One Pot ◽

X Ray ◽

Air Atmosphere ◽

Transmission Electron ◽

Ft Ir ◽

The One

A heterostructural composite composed of g-C3N4 and Bi2O3 was achieved by the one-pot and thermal-induced polycondensation method using melamine and Bi(NO[Formula: see text] as precursor at 550[Formula: see text]C under air atmosphere. The crystalline phase, components and morphologies of the as-prepared composites were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Besides, the photocatalytic activity of composites was evaluated by degrading RhB aqueous solution at room temperature under visible light irradiation. Compared with bulk g-C3N4, the photocatalytic efficiency of the 0.5% Bi2O3/g-C3N4 (Bi–CN) was increased by up to four times. The introduction of Bi2O3 enhances not only the light absorption ability, but also the separation of photogenerated electron–hole pairs.

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HYDROTHERMAL SYNTHESIS OF α-MoO3 NANORODS FOR NO2 DETECTION

International Journal of Nanoscience ◽

10.1142/s0219581x12400443 ◽

2012 ◽

Vol 11 (06) ◽

pp. 1240044 ◽

Cited By ~ 5

Author(s):

SHOULI BAI ◽

SONG CHEN ◽

YUAN TIAN ◽

RUIXIAN LUO ◽

DIANQING LI ◽

...

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Molybdenum Trioxide ◽

Hydrothermal Process ◽

High Sensitivity ◽

X Ray Diffraction ◽

Hydrothermal Temperature ◽

X Ray ◽

Transmission Electron ◽

Ft Ir

Thermodynamically stable molybdenum trioxide nanorods have been successfully synthesized by a simple hydrothermal process. The product exhibits high-quality, single-crystalline layered orthorhombic structure (α- MoO3 ), and aspect ratio over 20 by characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared (FT-IR). The growth mechanism of α- MoO3 nanorods can be understood by electroneutral and dehydration reaction, which is highly dependent on solution acidity and hydrothermal temperature. The sensing tests show that the sensor based on MoO3 nanorods exhibits high sensitivity to NO2 and is not interferred by CO and CH4 , which makes this kind sensor a competitive candidate for NO2 detection. The intrinsic sensing performance of MoO3 maybe arise from its nonstoichiometry of MoO3 owing to the presence of Mo5+ and oxygen vacancy in MoO3 lattice, which has been confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The sensing mechanism of MoO3 for NO2 is also discussed.

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Facile Synthesis of Phase Tunable MoO3 Nanostructures and Their Electrochemical Sensing Properties

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17456 ◽

2020 ◽

Vol 20 (5) ◽

pp. 2823-2831

Author(s):

S. Muthamizh ◽

C. Sengottaiyan ◽

R. Jayavel ◽

V. Narayanan

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Electrochemical Sensing ◽

X Ray Diffraction ◽

Facile Synthesis ◽

X Ray ◽

Solid State Decomposition ◽

Transmission Electron ◽

Vis Spectroscopy ◽

Ft Ir

MoO3 nanostructures with tunable phases such as α-MoO3, β-MoO3 and their mixed phases were synthesized via a simple solid state decomposition method and employed as electrocatalyst for the detection of biomolecule. The phase and crystal structure of the synthesized MoO3 nanostructures were confirmed through X-ray diffraction (XRD) studies. The MoO3 nanostructures were also characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy for their structural, chemical state and optical properties, respectively. The observed results confirmed the successful formation of phase tunable MoO3 nanostructures. The surface texture and morphology of the samples was characterized by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The obtained images showed the formation of hexagons, cubes and rods morphology of MoO3. The synthesized MoO3 nanostructures were used to modify the surface of glassy carbon electrode (GCE) to detect biomolecule (quercetin).

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A Facile Synthesis of Graphene-WO3Nanowire Clusters with High Photocatalytic Activity for O2Evolution

International Journal of Photoenergy ◽

10.1155/2014/943537 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6

Author(s):

M.-J. Zhou ◽

N. Zhang ◽

Z. H. Hou

Keyword(s):

Photocatalytic Activity ◽

Water Splitting ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

High Photocatalytic Activity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Charge Transfer Rate ◽

Ft Ir

In the present work, graphene-WO3nanowire clusters were synthesizedviaa facile hydrothermal method. The obtained graphene-WO3nanowire clusters were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (DRS) techniques. The photocatalytic oxygen (O2) evolution properties of the as-synthesized samples were investigated by measuring the amount of evolved O2from water splitting. The graphene-WO3nanowire clusters exhibited enhanced performance compared to pure WO3nanowire clusters for O2evolution. The amount of evolved O2from water splitting after 8 h for the graphene-WO3nanowire clusters isca.0.345 mmol/L, which is more than 1.9 times as much as that of the pure WO3nanowire clusters (ca.0.175 mmol/L). The high photocatalytic activity of the graphene-WO3nanowire clusters was attributed to a high charge transfer rate in the presence of graphene.

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Incorporation of Gold Nanoparticles Within Thermoresponsive Microgel Particles: Effect of Crosslinking Density

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.18383 ◽

2008 ◽

Vol 8 (12) ◽

pp. 6283-6289

Author(s):

Yang Dong ◽

Ying Ma ◽

Tianyou Zhai ◽

Yi Zeng ◽

Hongbing Fu ◽

...

Keyword(s):

Gold Nanoparticles ◽

Photoelectron Spectroscopy ◽

Trisodium Citrate ◽

Crosslinking Density ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Microgel Particles ◽

One Step ◽

Ft Ir

Hybrid microgel particles were prepared by one step incubation of poly(N-isopropylacrylamide)-co-poly(acrylic acid) (PNIPAM-co-PAA) and gold nanoparticles (AuNPs). PNIPAM-co-PAA microgel particles were synthesized by surfactant-free emulsion polymerization with different crosslinking densities (4.5 wt.-%, 10 wt.-%, 15 wt.-%, MBA to NIPAM) and AuNPs obtained by trisodium citrate reduction method independently. The effect of crosslinking density of synthesized microgel particles on the loadings of AuNPs was investigated. The results showed that 18±2 nm AuNPs could be well entrapped in the loosely crosslinked (4.5 wt.-%, MBA to NIPAM) PNIPAM-co-PAA microgel particles with high loadings. The final hybrid microgel particles were well characterized by transmission electron microscopy (TEM), UV-vis spectra, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and FT-IR. In particular, the PNIPAM-co-PAA/AuNPs hybrid microgel particles were thermoresponsive and completely reversible with several heating/cooling cycles. Therefore, the PNIPAM-co-PAA/AuNPs hybrid microgel particles allow for combined surface plasmon and thermal switching applications.

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Edge Functionalized Graphene Layers for (Ultra) High Exfoliation in Carbon Papers and Aerogels in the Presence of Chitosan

Materials ◽

10.3390/ma13010039 ◽

2019 ◽

Vol 13 (1) ◽

pp. 39

Author(s):

Silvia Guerra ◽

Vincenzina Barbera ◽

Alessandra Vitale ◽

Roberta Bongiovanni ◽

Andrea Serafini ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Graphene Layers ◽

Biobased Polymers ◽

Transmission Electron ◽

Wide Range ◽

Ft Ir ◽

Hydroxy Groups ◽

Thermal Stability Of

Ultra-high exfoliation in water of a nanosized graphite (HSAG) was obtained thanks to the synergy between a graphene layer edge functionalized with hydroxy groups and a polymer such as chitosan (CS). The edge functionalization of graphene layers was performed with a serinol derivative containing a pyrrole ring, serinol pyrrole (SP). The adduct between CS and HSAG functionalized with SP was formed simply with a mortar and pestle, then preparing water dispersions stable for months in the presence of acetic acid. Simple casting of such dispersions on a glass support led to carbon papers. Aerogels were prepared through the freeze-dry procedure. Exfoliation was observed in both these families of composites and ultra-high exfoliation was documented in aerogels swollen in water. Carbon papers and aerogels were stable for months in solvents in a wide range of solubility parameter and in a pretty wide range of pH. By considering that a moderately functionalized nanographite was straightforwardly exfoliated in water in the presence of one of the most abundant biobased polymers, the obtained results pave the way for the simple and sustainable preparation of graphene-based nanocomposites. HSAG–SP/CS adducts were characterized by wide angle X-ray diffraction (WAXD), scanning and transmission electron microscopy (SEM, TEM and HRTEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Thermal stability of the composites was studied by thermogravimetric analysis (TGA) and their direct electrical conductivity with the four-point probe method.

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α-Cellulose Fibers of Paper-Waste Origin Surface-Modified with Fe3O4 and Thiolated-Chitosan for Efficacious Immobilization of Laccase

Polymers ◽

10.3390/polym13040581 ◽

2021 ◽

Vol 13 (4) ◽

pp. 581

Author(s):

Gajanan S. Ghodake ◽

Surendra K. Shinde ◽

Ganesh D. Saratale ◽

Rijuta G. Saratale ◽

Min Kim ◽

...

Keyword(s):

Enzyme Immobilization ◽

Photoelectron Spectroscopy ◽

Cellulose Fibers ◽

Relative Activity ◽

Significant Activity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Laccase Immobilization ◽

Surface Modified

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

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