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Journal ArticleDOI: 10.1016/J.JHAZMAT.2020.124252

High-dispersed Fe2O3/Fe nanoparticles residing in 3D honeycomb-like N-doped graphitic carbon as high-performance room-temperature NO2 sensor

05 Mar 2021-Journal of Hazardous Materials (Elsevier)-Vol. 405, pp 124252-124252
Abstract: This work illustrates a simple polymer thermal treatment strategy to develop high-dispersed Fe2O3/Fe nanoparticles residing in honeycomb-like N-doped graphitic carbon (Fe2O3/Fe@N-GC). The as-prepared Fe2O3/Fe@N-GC composites consist of three-dimensional (3D) strutted interconnective graphitic carbon frame, which would not only refrain from restacking and facilitate the charge transfer, but also provide more reaction interface between gas molecules and materials. Benefiting from the synergistic merits of Fe2O3/Fe, N-doping graphitic carbon, high surface area and unique 3D architectures, the optimal Fe2O3/Fe@N-GC presents impressive sensitivity and selectivity for NO2 gas detection at room temperature with the response of 25.48–100 ppm, response time of 2.13 s, recovery time of 11.73 s, detection limit of 10 ppb and as long as 60 days of stability. As a result, the present Fe2O3/Fe@N-GC composite with an easy fabrication method and high sensitivity, selectivity, stabitliy towards NO2 at RT would inspire various designs based on the 3D honeycomb structure for more real applications in gas sensors.

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Topics: Honeycomb structure (53%)
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6 results found


Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.125830
Xue Bai1, He Lv1, Zhuo Liu1, Junkun Chen1  +5 moreInstitutions (1)
Abstract: The unique properties of heterostructure materials make them become a promising candidate for high-performance room-temperature (RT) NO2 sensing. Herein, a p-n heterojunction consisting of two-dimensional (2D) MoS2 nanoflakes vertically grown on one-dimensional (1D) SnO2 nanotubes (NTs) was fabricated via electrospinning and subsequent hydrothermal route. The sulfur edge active sites are fully exposed in the MoS2@SnO2 heterostructure due to the vertically oriented thin-layered morphology features. Moreover, the interface of p-n heterojunction provides an electronic transfer channel from SnO2 to MoS2, which enables MoS2 act as the generous electron donor involved in NO2 gas senor detection. As a result, the optimized MoS2@SnO2-2 heterostructure presents an impressive sensitivity and selectivity for NO2 gas detection at RT. The response value is 34.67 (Ra/Rg) to 100 ppm, which is 26.5 times to that of pure SnO2. It also exhibits a fast response and recovery time (2.2 s, 10.54 s), as well as a low detection limit (10 ppb) and as long as 20 weeks of stability. This simple fabrication of high-performance sensing materials may facilitate the large-scale production of RT NO2 gas sensors.

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Topics: Heterojunction (53%)

7 Citations


Open accessJournal ArticleDOI: 10.1039/D1TA03578A
Muhammad Ikram1, He Lv2, Zhuo Liu2, Keying Shi2  +1 moreInstitutions (2)
Abstract: Two-dimensional transition metal dichalcogenides (2D-TMDs) and semiconductor metal oxides (MOs) have triggered enormous research attention in the fields of energy storage, catalysis, and gas sensing. However, the poor stability of TMDs in air and the high operating temperature of MOs remain critical bottlenecks for their application in practical gas sensing. In this work, a hydrothermal method was developed to convert rhombic p–p MoS2@ZIF-8 into rodlike p–n MoS2@ZnO heterostructure at 150 °C, which displays a large surface area, strong interaction between MoS2 and ZnO, and fast electron transportation. The as-synthesized p–n heterostructure was used to construct a gas sensor for the detection of NO2 at room temperature in air. The sensor showed an over 30-fold enhancement in the response compared to that of pristine MoS2 nanosheets and displayed short response/recovery time while lowering the detection limit of NO2 to 10 ppb. The sensor retained high stability upon sensing repetition for 10 consecutive weeks. This work demonstrated a facile strategy for the synthesis of p–n MoS2–ZnO heterostructures for reliable NO2 gas sensing at room temperature.

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Topics: Semiconductor (50%)

4 Citations


Journal ArticleDOI: 10.1016/J.APCATB.2021.120546
Lang He1, Wenyuan Zhang2, Sheng Liu1, Yan Zhao1Institutions (2)
Abstract: A facile polymer thermal treatment method has been employed to fabricate 3D porous N-doped graphitic carbon frameworks with embedded CoO (CoO@N-GCs), which are employed as catalysts for the photocatalytic reduction of CO2. The experimental results demonstrate that the CoO@N-GC-500 catalyst exhibits excellent photocatalytic performance and stability for the photoreduction of CO2 in water. Under visible light irradiation, the maximum yields for CH4 and CO are 10.03 μmol/(h·g) and CO is 5.16 μmol/(h·g), respectively. The high photocatalytic performance of CoO@N-GC-500 is attributed to the efficient separation of the photogenerated electron-hole pairs, large specific surface area, and strong visible light absorption capacity. This work paves a new way for the practical application of the CoO catalysts in artificial photosynthesis.

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3 Citations


Journal ArticleDOI: 10.1021/ACS.ANALCHEM.1C03102
Jia-Li Liu1, Rong Yang1, Yaqin Chai1, Ruo Yuan1Institutions (1)
Abstract: Herein, a versatile ECL biosensor was fabricated for ultrasensitive detection of microRNA-21 (miRNA-21) from cancer cells based on a novel H2O2-free electrochemiluminescence (ECL) system (luminol/dissolved oxygen/Fe@Fe2O3 nanowires). Compared with the previously reported coreaction accelerator that needed a negative potential to produce reactive oxygen species (ROS), these newly discovered Fe@Fe2O3 nanowires could generate ROS in the detection solution immediately without the application of voltage, which narrowed down the detection potential range to avoid side reactions, favoring their practical application in biological systems. Especially, the Fe@Fe2O3 nanowires could produce H• for activating dissolved oxygen into ROS to improve the ECL intensity dramatically, which initiates a novel pathway to promote the generation of ROS for the ECL system. In addition, an original strand displacement amplification coupled with strand displacement reaction (SDA-SDR) was developed to improve the conversion efficiency of the target for sensitive detection of miRNA-21. By virtue of the SDR, a quadruple quenching effect was achieved through each output DNA strand of SDA; hence, the nucleic acid signal amplification efficiency was effectively enhanced. As expected, on account of the superb activation performance of Fe@Fe2O3 nanowires and the outstanding amplification efficiency of the SDR-SDA strategy, the fabricated ECL biosensor realized ultrasensitive detection of miRNA-21 with a detection limit down to 52.5 aM. The established ECL sensing platform ushered a new route for H2O2-free detection and a promising biomarker assay method for clinical diagnosis.

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Topics: Electrochemiluminescence (52%)

1 Citations


Journal ArticleDOI: 10.1016/J.PHYSE.2021.114807
Yong-Hui Zhang1, Chao-Nan Wang1, Li-Juan Yue1, Junli Chen1  +2 moreInstitutions (1)
Abstract: Nitrogen dioxide (NO 2 ), as a toxic gas, seriously harms the environment and human health. Semiconductor metal oxide (MOS) nanocomposites modified by N-doped graphene quantum dots (N-GQDs) have attracted extensive attention as sensing materials for NO 2 . Here, the N-GQDs modified ZnO composite material was successfully prepared by the hydrothermal method . Compared with pure ZnO, G-Z-2 (N-GQD S doping amount of 2 mL) exhibits excellent sensing performance for NO2. The G-Z-2 based sensor reduces the working temperature from 160 °C to 100 °C. The G-Z-2 is shown to be sensitive to 5 ppm NO2 and has a massively enhanced response of about 11.6 times. The detection limit was as low as 0.1 ppm. Moreover, it shows excellent reproducibility, selectivity and stability for the detection of NO 2 . The highly active N atom doping enhances the electron transfer of ZnO to N-GQD S and the adsorption of NO2 molecules. The heterojunction between ZnO and N-GQD S interface expands the resistance modulation, which improves the sensor sensitivity. This work can provide a promising strategy for improving the NO2 gas sensing performance based on semiconductor metal oxide.

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Topics: Graphene (55%), Doping (53%), Quantum dot (52%) ... read more

1 Citations


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84 results found


Journal ArticleDOI: 10.1002/ADMA.201503825
Jun Zhang1, Jun Zhang2, Xianghong Liu1, Giovanni Neri3  +1 moreInstitutions (4)
01 Feb 2016-Advanced Materials
Abstract: Sensor technology has an important effect on many aspects in our society, and has gained much progress, propelled by the development of nanoscience and nanotechnology. Current research efforts are directed toward developing high-performance gas sensors with low operating temperature at low fabrication costs. A gas sensor working at room temperature is very appealing as it provides very low power consumption and does not require a heater for high-temperature operation, and hence simplifies the fabrication of sensor devices and reduces the operating cost. Nanostructured materials are at the core of the development of any room-temperature sensing platform. The most important advances with regard to fundamental research, sensing mechanisms, and application of nanostructured materials for room-temperature conductometric sensor devices are reviewed here. Particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations. Finally, some future research perspectives and new challenges that the field of room-temperature sensors will have to address are also discussed.

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868 Citations


Open accessJournal ArticleDOI: 10.1021/ACSNANO.5B04343
Jian Zhen Ou1, Wanyin Ge2, Benjamin J. Carey1, Torben Daeneke1  +11 moreInstitutions (3)
13 Oct 2015-ACS Nano
Abstract: Nitrogen dioxide (NO2) is a gas species that plays an important role in certain industrial, farming, and healthcare sectors. However, there are still significant challenges for NO2 sensing at low detection limits, especially in the presence of other interfering gases. The NO2 selectivity of current gas-sensing technologies is significantly traded-off with their sensitivity and reversibility as well as fabrication and operating costs. In this work, we present an important progress for selective and reversible NO2 sensing by demonstrating an economical sensing platform based on the charge transfer between physisorbed NO2 gas molecules and two-dimensional (2D) tin disulfide (SnS2) flakes at low operating temperatures. The device shows high sensitivity and superior selectivity to NO2 at operating temperatures of less than 160 °C, which are well below those of chemisorptive and ion conductive NO2 sensors with much poorer selectivity. At the same time, excellent reversibility of the sensor is demonstrated, which has rarely been observed in other 2D material counterparts. Such impressive features originate from the planar morphology of 2D SnS2 as well as unique physical affinity and favorable electronic band positions of this material that facilitate the NO2 physisorption and charge transfer at parts per billion levels. The 2D SnS2-based sensor provides a real solution for low-cost and selective NO2 gas sensing.

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432 Citations


Journal ArticleDOI: 10.1016/J.APCATB.2011.08.027
Shijian Yang1, Shijian Yang2, Chizhong Wang1, Junhua Li1  +3 moreInstitutions (2)
Abstract: (Fe3−xMnx)1−δO4 was synthesized using a co-precipitation method and then developed as a catalyst for the low temperature selective catalytic reduction (SCR) of NO with NH3. The SCR activity of (Fe3−xMnx)1−δO4 was clearly enhanced with the increase of Mn content. The results of in situ DRIFTS study demonstrated that both the Eley–Rideal mechanism (i.e. reaction of activated ammonia with gaseous NO) and the Langmuir–Hinshelwood mechanism (i.e. reaction of adsorbed ammonia species with adsorbed NOx species) might happen during the SCR reaction over (Fe3−xMnx)1−δO4. According to the kinetic analysis, the respective contribution of the Langmuir–Hinshelwood mechanism and the Eley–Rideal mechanism on the SCR reaction was studied. Only the adsorption of NO + O2 on (Fe2.8Mn0.2)1−δO4 was promoted, so the Langmuir–Hinshelwood mechanism predominated over NO conversion on (Fe2.8Mn0.2)1−δO4 especially at lower temperatures. Both the adsorption of NO + O2 and the adsorption of NH3 on (Fe2.5Mn0.5)1−δO4 were obviously promoted, so NO conversion on (Fe2.5Mn0.5)1−δO4 mainly followed the Eley–Rideal mechanism especially at higher temperatures. Both the nitrate route and the over-oxidization of adsorbed ammonia species contributed to the formation of N2O on (Fe2.8Mn0.2)1−δO4 above 140 °C. However, the formation of N2O on (Fe2.5Mn0.5)1−δO4 mainly resulted from the over-oxidization of adsorbed ammonia species. Although the activity of (Fe2.5Mn0.5)1−δO4 was suppressed in the presence of H2O and SO2, the deactivated catalyst can be regenerated after the water washing.

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Topics: Selective catalytic reduction (56%), Catalysis (52%), Adsorption (50%)

330 Citations


Journal ArticleDOI: 10.1021/CS401185C
Lei Zhang1, Liyi Shi1, Lei Huang1, Jianping Zhang1  +2 moreInstitutions (1)
01 May 2014-ACS Catalysis
Abstract: Herein, we have rationally designed and originally developed a high-performance deNOx catalyst based on hollow porous MnxCo3–xO4 nanocages with a spinel structure thermally derived from nanocube-like metal–organic frameworks (Mn3[Co(CN)6]2·nH2O), which are synthesized via a self-assemble method. The as-prepared catalysts have been characterized systematically to elucidate their morphological structure and surface properties. As compared with conventional MnxCo3–xO4 nanoparticles, MnxCo3–xO4 nanocages possess a much better catalytic activity at low-temperature regions, higher N2 selectivity, more extensive operating-temperature window, higher stability, and SO2 tolerance. The feature of hollow and porous structures provides a larger surface area and more active sites to adsorb and activate reaction gases, resulting in the high catalytic activity. Moreover, the uniform distribution and strong interaction of manganese and cobalt oxide species not only enhance the catalytic cycle but also inhibit the formatio...

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Topics: Nanocages (66%), Catalytic cycle (51%), Metal-organic framework (51%) ... read more

318 Citations


Journal ArticleDOI: 10.1039/B907584D
Abstract: The adsorption of nitrogen dioxide on gamma aluminium oxide (gamma-Al(2)O(3)) and alpha iron oxide (alpha-Fe(2)O(3)) particle surfaces under various conditions of relative humidity, presence of molecular oxygen and UV light has been investigated. X-Ray photoelectron spectroscopy (XPS) is used to monitor the different surface species that form under these environmental conditions. Adsorption of NO(2) on aluminum oxide particle surfaces results primarily in the formation of surface nitrate, NO(3)(-) with an oxidation state of +5, as indicated by a peak with binding energy of 407.3 eV in the N1s region. An additional minority species, sensitive to the presence of relative humidity and molecular oxygen, is also observed in the N1s region with lower binding energy of 405.9 eV. This peak is assigned to a surface species in the +4 oxidation state. When irradiated with UV light, other species form on the surface. These surface-bound photochemical products all have lower binding energy, between 400 and 402 eV, indicating reduced nitrogen species in the range of N oxidations states spanning +1 to -1. Co-adsorbed water decreases the amount of these reduced surface-bound products while the presence of molecular oxygen completely suppresses the formation of all reduced nitrogen species on aluminum oxide particle surfaces. For NO(2) on iron oxide particle surfaces, photoreduction is enhanced relative to gamma-Al(2)O(3) and surface bound photoreduced species are observed under all environmental conditions. Complementing the experimental data, N1s core electron binding energies (CEBEs) were calculated using DFT for a number of nitrogen-containing species in the gas phase and adsorbed on an Al(8)O(12) cluster. A range of CEBEs is calculated for various nitrogen species in different adsorption modes and oxidation states. These calculated values are discussed in light of the peaks observed in the XPS N1s region and the possible species that form following NO(2) adsorption and photoreaction on metal oxide particle surfaces under different conditions of relative humidity, presence of molecular oxygen and UV light.

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Topics: Oxide (59%), Adsorption (55%), X-ray photoelectron spectroscopy (53%) ... read more

180 Citations