Functionalized MWCNTs effects on dramatic enhancement of MWCNTs/SnO 2 nanocomposite gas sensing properties at low temperatures

Naghadeh, Sara Bonabi; Vahdatifar, Sahar; Mortazavi, Yadollah; Khodadadi, Abbas Ali; Abbasi, Alireza

doi:10.1016/j.snb.2015.09.088

Cited by 33 publications

(8 citation statements)

References 45 publications

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“…Using the Arrhenius equation, we determined the activation energy of the ZnO–MWCNT (15:1) composite to be 0.24 eV, which is higher than that of pure ZnO hollow spheres (0.21 eV) (Figure S8). Moreover, the presence of the p–n heterojunction not only generates additional barrier potential but also increases the chemisorption of oxygen molecules. ,− As a result, the change in resistance of the ZnO–MWCNT (15:1) composite upon exposure to SO 2 gas is higher than that of ZnO hollow spheres.…”

Section: Resultsmentioning

confidence: 99%

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

Septiani

Saputro

Kaneti

et al. 2020

ACS Appl. Nano Mater.

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This work reports the first utilization of anthocyanin extracted from black rice (Oryza sativa L.) grains as a structure-directing agent for the synthesis of hollow zinc oxide (ZnO) spheres via a simple solvothermal reaction and their subsequent modifications with various amounts of multiwalled carbon nanotubes (MWCNTs). Following hybridization with MWCNTs, some MWCNTs are observed to penetrate into the inner cavities of the spheres, while ZnO nanoparticles are formed on the surface of some MWCNTs. When employed as a sulfur dioxide (SO 2 ) sensor, the ZnO−MWCNT (15:1) composite displays a high response of 156 to 70 ppm of SO 2 at an optimum temperature of 300 °C as well as good selectivity to SO 2 with the response to 50 ppm of SO 2 gas being 3 times higher than those to other gases, such as CO, CO 2 , methanol, toluene, hexane, and xylene. Interestingly, the sensing behavior of this composite is strongly influenced by the proportion of MWCNTs. Specifically, n-type sensing behavior is observed for both ZnO−MWCNT (10:1) and (15:1) composites, while p-type behavior is observed for the ZnO−MWCNT (5:1) composite. The switch in sensing behavior suggests the major contribution of p-type MWCNTs to the electronic and sensing properties of the ZnO/MWCNT composites. The density functional theory (DFT) simulations on the adsorption of SO 2 on the ZnO/CNT system reveal that the SO 2 molecule only chemically interacts with the O adatom of ZnO (i.e., oxygen atom adsorbed on the surface of ZnO) to form sulfur trioxide (SO 3 ), and charge transfer is observed from ZnO to CNT, which enhances the change in resistance of the composite sensor upon exposure to SO 2 gas.

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Section: Resultsmentioning

confidence: 99%

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

Septiani

Saputro

Kaneti

et al. 2020

ACS Appl. Nano Mater.

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“…MWCNTs are cylindrical nanoparticles combined with multiple graphene layers with their shapes, sizes, and unusual physical properties. In addition, MWCNTs act as a scaffold for the insertion of many metal nanoparticles due to their large surface area 40 – 42 . The ratios of I D /I G for NiCu@MWCNT nanohybrids and MWCNT were found to be 1.38 and 1.22, respectively.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of benzylidenemalononitrile by Knoevenagel condensation through monodisperse carbon nanotube-based NiCu nanohybrids

Zengin

Burhan

Şavk

et al. 2020

Sci Rep

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Monodisperse nickel/copper nanohybrids (nicu@MWcnt) based on multi-walled carbon nanotubes (MWcnt) were prepared for the Knoevenagel condensation of aryl and aliphatic aldehydes. the synthesis of these nanohybrids was carried out by the ultrasonic hydroxide assisted reduction method. nicu@MWcnt nanohybrids were characterized by analytical techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (teM), high-resolution transmission electron microscopy (HR-teM), and Raman spectroscopy. According to characterization results, nicu@MWcnt showed that these nanohybrids form highly uniform, crystalline, monodisperse, colloidally stable nicu@MWcnt nanohybrids were successfully synthesized. thereafter, a model reaction was carried out to obtain benzylidenemalononitrile derivatives using nicu@MWcnt as a catalyst, and showed high catalytic performance under mild conditions over 10-180 min. Benzylidenemalononitrile (BMN) derivatives are frequently used as both a target molecule and an intermediate molecule in organic chemistry. BMN derivatives have attracted many scientists' attention because of some unique properties such as anticancer 1-3 , antifungal 4,5 , antibacterial 6-9 , anti-corrosive 10. BMN derivatives are used to increase cell resistance in the case of oxidative stress 11 , in prostaglandin biosynthesis 12 , in the design of photoconductive cells 13 and the inhibition/activation of certain enzymes 14,15. Typically, BMN derivatives are synthesized by the Knoevenagel condensation of aldehydes with active methylene compounds (Fig. 1) 16-22. In these processes, it is seen that it has an effect on homogeneous catalysts. Heterogeneous catalysts have various advantages such as minimum availability, recovery, reusability, structural deterioration resistance and leaching of metal values 23-28. Bimetallic heterogeneous catalysts, in particular, have greatly facilitated the Knoevenagel condensation reaction 29-34. In literature, many catalysts such as SBA-15 (highly stable mesoporous silica) 35 , Sr 3 Al 2 O 6 nanoparticles 36 , bifunctional MIL-101(Cr) 37 , Fe 3 O 4 @SiO 2 nanoparticles 38 and Mn-MOF@Pi 39 have been used in condensation reactions. Herein we report an eco-friendly and practical method for the synthesis of highly efficient, cost-effective, and monodisperse bimetallic NiCu@MWCNT nanohybrids for the Knoevenagel condensation reaction under mild conditions. BMN derivatives have been successfully obtained in a very short time (10-180 min) using the developed method in the water-containing solvent system. experimental chemicals. NiCl 2 , CuCl 2 , NaBH 4 , aminoborane aryl azides, acetonitrile (ACN), lithium perchlorate (LiClO 4), 3,4-ethylene dioxythiophene (EDOT), multiwall carbon nanotubes, NN-Dimethylformamide (DMF), sulfuric acid, hydrochloric acid, and nitric acid were purchased from Sigma-Aldrich. Tetrahydrofuran (THF; 99.5%), HClO 4 (60%), 2-propanol, and Methanol (≥ 99.5%) were obtained from Merck. All test materials and other

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“…The wild mustard oil (brassica oil) is extracted from the Indian mustard seeds which can be distinctively cultivated for seeds and their flash, fire and pour points are 329°C, 340°C and -15.8°C, respectively. It is used as base oil for coining MWCNT-Mustard oil nanofluid (0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt% and 1 wt%) by ultrasonication technique [17][18]. The weight of MWCNT was measured by a precise digital weighing balance (accuracy of 0.01mg).…”

Section: Methodsmentioning

confidence: 99%

Experimental Investigation and Mechanism Analysis: Effect of Concentration and Temperature on the Viscosity of Novel MWCNT-Mustard Oil Nanofluid

Vignesh¹,

Vijayan²,

Selvakumar³

2020

J. Chil. Chem. Soc.

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The bio-oils as alternative lubricating fluid are potential solution for the automotive and industrial mechanical systems. The development of novel renewable and non-toxic bio-lubricants with better lubricating distinctiveness will strengthen the economy of farmers in the agricultural based countries. In the present study, different weight fractions of MWCNT-Mustard oil nanofluids are formulated and their possible effects on the dispersion stability and dynamic viscosity are experimentally investigated over the temperatures ranging from 40 to 100°C. It is observed that the dynamic viscosity and viscosity index of nanofluids were declined with temperature raise, while, it exponentially increased with the raise of MWCNT concentration. The maximum viscosity enhancement of 101.3% is achieved in comparison to the base fluid at 100ºC. Further, the dynamic viscosity of nanofluids is compared with different classical semi-empirical correlations, however, the remarkable conformities were observed from multilayer feed forward Perceptron (MLP) of artificial neural network (ANN).

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Functionalized MWCNTs effects on dramatic enhancement of MWCNTs/SnO 2 nanocomposite gas sensing properties at low temperatures

Cited by 33 publications

References 45 publications

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

Synthesis of benzylidenemalononitrile by Knoevenagel condensation through monodisperse carbon nanotube-based NiCu nanohybrids

Experimental Investigation and Mechanism Analysis: Effect of Concentration and Temperature on the Viscosity of Novel MWCNT-Mustard Oil Nanofluid

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