Controllable synthesis of Co3O4/polyethyleneimine-carbon nanotubes nanocomposites for CO and NH3 gas sensing at room temperature

Lin, Yufei; Kan, Kan; Song, Wanzhen; Zhang, Guo; Dang, Lifang; Xie, Yu; Shen, Pei Kang; Li, Li; Shi, Keying

doi:10.1016/j.jallcom.2015.03.139

Cited by 43 publications

(20 citation statements)

References 53 publications

(51 reference statements)

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“…Heterostructures were reported to offer better gas sensing characteristics in terms of sensing response, speed of response, operation temperature and selectivity as compared to their pure metal oxide counterparts. The enhancement originates from wider light absorption spectrum, increasing carrier concentrations and the benefit of combining the merits of constituent materials [ 29 , 32 ]. Different combinations of materials for the formation of heterostructures have been reported.…”

Section: Metal Oxide Materials Composites and Metal Oxide With Dopmentioning

confidence: 99%

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Light-Activated Metal Oxide Gas Sensors: A Review

Fang

2017

Micromachines

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Conductometric gas sensors facilitated by photons have been investigated for decades. Light illumination may enhance device attributes including operational temperature, sensing sensitivity and selectivity. This paper aims to provide an overview on the progress of light-activated gas sensors, with a specific focus on sensors based on metal oxides. The material systems that have been studied include pure metal oxides, heterostructures of semiconductor-metal oxides and metal-metal oxides, and metal oxides with dopant. Other reported works on the use of different nanostructures such as one-dimensional and porous nanostructures, study of sensing mechanisms and the interplay between various factors are also summarized. Possible directions for further improvement of sensing properties, through optimizing the size of nanomaterials, film thickness, light intensity and wavelength are discussed. Finally, we point out that the main challenge faced by light-activated gas sensors is their low optical response, and we have analyzed the feasibility of using localized surface plasmon resonance to solve this drawback. This article should offer readers some key and instructive insights into the current and future development of light-activated gas sensors.

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Section: Metal Oxide Materials Composites and Metal Oxide With Dopmentioning

confidence: 99%

“…It will also limit the sensor’s application in the detection of flammable or explosive analytes because of safety issues. Thus, an important research aim in the conductometric gas sensor is to lower the working temperature [ 24 , 30 , 31 , 32 , 33 , 34 ], Photon activation hence becomes an obvious choice.…”

Section: Introductionmentioning

confidence: 99%

Light-Activated Metal Oxide Gas Sensors: A Review

Fang

2017

Micromachines

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“…Furthermore, Lin et al. exploited the gas‐sensing characteristics of a 1D

{Co}_{3} O_{4}

/polyethyleneimine–carbon‐nanotube composite (). Development of such complexes may open up a constructive approach to create low‐cost and large‐scale production of carbon monoxide and NH

_{3}

gas sensors.…”

Section: Introductionmentioning

confidence: 99%

“…Development of such complexes may open up a constructive approach to create low‐cost and large‐scale production of carbon monoxide and NH

_{3}

gas sensors. The majority of the reports in the literature are focused on the catalytic properties, gas‐sensing features, and enhanced electrode performance in Li‐ion batteries by either substituting different elements within the

{Co}_{3} O_{4}

matrix or making nanocomposites consisting of

{Co}_{3} O_{4}

.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic studies of Co₂TiO₄ and Co₃O₄ two‐phase composites

Nayak

Dasari

Joshi

et al. 2016

Physica Status Solidi (b)

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In this article, we report a comparative analysis of various spectroscopic studies including low‐temperature (25thinmathspacenormalKthinmathspace≤T≤300normalK) Raman spectroscopy of cobalt‐orthotitanate (Co2TiO4) and tricobalt‐tetraoxide (Co3O4), and their solid solutions false(1−xfalse) Co3O4+x of Co2TiO4 (0≤x≤1 (100 wt.%)). For all the lower and intermediate compositions, five Raman‐active modes were recognized at 689, 618, 518, 480, and 195cm−1 that are associated with A1g, Eg, and 3F2g phonon symmetries. Conversely, pure Co2TiO4 exhibits a broad spectrum of width ∼93.3cm−1 without any signatures of F2g(3) mode. At low‐temperatures (down to 25 K) the A1g and F2g peaks of both Co2TiO4 and Co3O4 shift toward the high‐frequency side with anomalies across the ferrimagnetic Néel temperature (TN ∼48±5K) and antiferromagnetic Néel temperature (TN∼ 30 ± 10 K), respectively. All the investigated samples exhibit two distinct bands at 576cm−1 (B1) and 665cm−1 (B2) in the Fourier transform infrared spectra recorded at 300±10 K, associated with the vibrational stretching of the metal–oxygen bonds of length ∼195.8 pm (B–O) and ∼185.4 pm (A–O), respectively. The intensity of these sharp bands gradually decreases as the crystal structure transforms from normal‐spinel (a=8.07 Å) to inverse‐spinel structure (a=8.45 Å). The X‐ray photoelectron spectroscopy (XPS) studies revealed that the Ti was incorporated into the octahedral B‐sites of inverse‐spinel structure of Co2TiO4. Interestingly, the XPS spectra of Co2TiO4 provide evidence of the trivalent character of Ti instead of tetravalent cationic configuration together with a weak Co3+ character at the octahedral sites. These results are discussed in terms of the binding‐energy (BE) difference between the O‐1s and Ti‐2p3/2 (Δ[O–Ti‐2p3/2] = BE(O‐1s) −BE(Ti‐2p3/2false)) and the mean chemical bond length lfalse[italicTi−Ofalse]. The peculiarities of all these results in consonance with the crystal‐structure (bond angles and bond lengths) and electron‐spin‐resonance studies are discussed in detail.

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“…Gas sensors are interesting as they can provide information about the composition of their ambient atmosphere and can detect low concentrations of volatile organic compounds on platforms tiny enough to be used on a microchip [1][2][3]. Gas sensors made from metal oxide semiconductors have been fabricated widely owing to the changes in its electrical conductivity under exposure to the test gases.…”

Section: Introductionmentioning

confidence: 99%