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12 pages, 3907 KiB

Open AccessArticle

High Sensitivity of Ammonia Sensor through 2D Black Phosphorus/Polyaniline Nanocomposite

by Zuquan Wu, Lei Liang, Shibu Zhu, Yifan Guo, Yao Yao, Yong Yang, Shifu Gu and Zuowan Zhou

Nanomaterials 2021, 11(11), 3026; https://doi.org/10.3390/nano11113026 - 11 Nov 2021

Cited by 10 | Viewed by 1989

Abstract

Recently, as a two-dimensional (2D) material, black phosphorous (BP) has attracted more and more attention. However, few efforts have been made to investigate the BP/polyaniline (PANI) nanocomposite for ammonia (NH₃) gas sensors. In this work, the BP/PANI nanocomposite as a novel [...] Read more.

Recently, as a two-dimensional (2D) material, black phosphorous (BP) has attracted more and more attention. However, few efforts have been made to investigate the BP/polyaniline (PANI) nanocomposite for ammonia (NH₃) gas sensors. In this work, the BP/PANI nanocomposite as a novel sensing material for NH₃ detection, has been synthesized via in situ chemical oxidative polymerization, which is then fabricated onto the interdigitated transducer (IDTs). The electrical properties of the BP/PANI thin film are studied in a large detection range from 1 to 4000 ppm, such as conduction mechanism, response, reproducibility, and selectivity. The experimental result indicates that the BP/PANI sensor shows higher sensitivity and larger detection range than that of PANI. The BP added into PANI, that may enlarge the specific surface area, obtain the special trough structure for gas channels, and form the p–π conjugation system and p–p isotype heterojunctions, which are beneficial to increase the response of BP/PANI to NH₃ sensing. Meanwhile, in order to support the discussion result, the structure and morphology of the BP/PANI are respectively measured by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV−vis), transmission electron microscopy (TEM), and field emissions scanning electron microscopy (SEM). Moreover, the sensor shows good reproducibility, and fast response and recovery behavior, on NH₃ sensing. In addition, this route may offer the advantages of an NH₃ sensor, which are of simple structure, low cost, easy to assemble, and operate at room temperature. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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13 pages, 2825 KiB

Open AccessArticle

First-Principles Study of Au-Doped InN Monolayer as Adsorbent and Gas Sensing Material for SF₆ Decomposed Species

by Ruochen Peng, Qu Zhou and Wen Zeng

Nanomaterials 2021, 11(7), 1708; https://doi.org/10.3390/nano11071708 - 29 Jun 2021

Cited by 14 | Viewed by 1918

Abstract

As an insulating medium, sulfur hexafluoride (SF₆) is extensively applied to electrical insulation equipment to ensure its normal operation. However, both partial discharge and overheating may cause SF₆ to decompose, and then the insulation strength of electrical equipment will be [...] Read more.

As an insulating medium, sulfur hexafluoride (SF₆) is extensively applied to electrical insulation equipment to ensure its normal operation. However, both partial discharge and overheating may cause SF₆ to decompose, and then the insulation strength of electrical equipment will be reduced. The adsorption properties and sensing mechanisms of four SF₆ decomposed components (HF, SO₂, SOF₂ and SO₂F₂) upon an Au-modified InN (Au-InN) monolayer were studied in this work based on first-principles theory. Meanwhile, the adsorption energy (E_ad), charge transfer (Q_T), deformation charge density (DCD), density of states (DOS), frontier molecular orbital and recovery property were calculated. It can be observed that the structures of the SO₂, SOF₂ and SO₂F₂ molecules changed significantly after being adsorbed. Meanwhile, the E_ad and Q_T of these three adsorption systems are relatively large, while that of the HF adsorption system is the opposite. These phenomena indicate that Au-InN monolayer has strong adsorption capacity for SO₂, SOF₂ and SO₂F₂, and the adsorption can be identified as chemisorption. In addition, through the analysis of frontier molecular orbital, it is found that the conductivity of Au-InN changed significantly after adsorbing SO₂, SOF₂ and SO₂F₂. Combined with the analysis of the recovery properties, since the recovery time of SO₂ and SO₂F₂ removal from Au-InN monolayer is still very long at 418 K, Au-InN is more suitable as a scavenger for these two gases rather than as a gas sensor. Since the recovery time of the SOF₂ adsorption system is short at 418 K, and the conductivity of the system before and after adsorption changes significantly, Au-InN is an ideal SOF₂ gas-sensing material. These results show that Au-InN has broad application prospects as an SO₂, SOF₂ and SO₂F₂ scavenger and as a resistive SOF₂ sensor, which is of extraordinary meaning to ensure the safe operation of power systems. Our calculations can offer a theoretical basis for further exploration of gas adsorbent and resistive sensors prepared by Au-InN. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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11 pages, 2947 KiB

Open AccessArticle

First-Principles Insight into Pd-Doped C₃N Monolayer as a Promising Scavenger for NO, NO₂ and SO₂

by Ruochen Peng, Qu Zhou and Wen Zeng

Nanomaterials 2021, 11(5), 1267; https://doi.org/10.3390/nano11051267 - 12 May 2021

Cited by 16 | Viewed by 2114

Abstract

The adsorption and sensing behavior of three typical industrial toxic gases NO, NO₂ and SO₂ by the Pd modified C₃N monolayer were studied in this work on the basic first principles theory. Meanwhile, the feasibility of using the Pd [...] Read more.

The adsorption and sensing behavior of three typical industrial toxic gases NO, NO₂ and SO₂ by the Pd modified C₃N monolayer were studied in this work on the basic first principles theory. Meanwhile, the feasibility of using the Pd doped C₃N monolayer (Pd-C₃N) as a sensor and adsorbent for industrial toxic gases was discussed. First, the binding energies of two doping systems were compared when Pd was doped in the N-vacancy and C-vacancy sites of C₃N to choose the more stable doping structure. The result shows that the doping system is more stable when Pd is doped in the N-vacancy site. Then, on the basis of the more stable doping model, the adsorption process of NO, NO₂ and SO₂ by the Pd-C₃N monolayer was simulated. Observing the three gases adsorption systems, it can be found that the gas molecules are all deformed, the adsorption energy (E_ad) and charge transfer (Q_T) of three adsorption systems are relatively large, especially in the NO₂ adsorption system. This result suggests that the adsorption of the three gases on Pd-C₃N belongs to chemisorption. The above conclusions can be further confirmed by subsequent deformable charge density (DCD) and density of state (DOS) analysis. Besides, through analyzing the band structure, the change in electrical conductivity of Pd-C₃N after gas adsorption was studied, and the sensing mechanism of the resistive Pd-C₃N toxic gas sensor was obtained. The favorable adsorption properties and sensing mechanism indicate that the toxic gas sensor and adsorbent prepared by Pd-C₃N have great application potential. Our work may provide some guidance for the application of a new resistive sensor and gas adsorbent Pd-C₃N in the field of toxic gas monitoring and adsorption. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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10 pages, 2074 KiB

Open AccessArticle

The Effect of Graphene Nanofiller on the Surface Structure and Performance of Epoxy Resin–Polyhedral Oligomeric Silsesquioxane (EP-POSS)

by Yanhong Fang, Ping Wang, Lifang Sun and Linhong Wang

Nanomaterials 2021, 11(4), 841; https://doi.org/10.3390/nano11040841 - 25 Mar 2021

Cited by 6 | Viewed by 2045

Abstract

Epoxy resin–polyhedral oligomeric silsesquioxane (EP-POSS) has excellent mechanical properties and hydrophobic properties. In order to adapt for application in sensor and photovoltaic fields, graphene, nano-SiO₂ and nano-ZnO were used to modify EP-POSS. FTIR was used to characterize changes on the surface structure [...] Read more.

Epoxy resin–polyhedral oligomeric silsesquioxane (EP-POSS) has excellent mechanical properties and hydrophobic properties. In order to adapt for application in sensor and photovoltaic fields, graphene, nano-SiO₂ and nano-ZnO were used to modify EP-POSS. FTIR was used to characterize changes on the surface structure after introducing nanoparticles. The change of hydrophobicity was measured using a contact angle test. TEM test results showed that nanoparticles were successfully inserted between the graphene sheets. However, the content of Si on the surface was low, as the cage structure of POSS in the molecular chain was coated by epoxy groups. XRD tests indicated that nanoparticles facilitated the dispersion of graphene in EP-POSS. XPS characterized the chemical state and content of the elements, confirming that the addition of graphene can induce the enrichment of Si on the surface of EP-POSS, which had a shielding effect on the main chain and improved the hydrophobicity. Wear resistance and adhesion tests showed that, after the introduction of nanoparticles, the EP-POSS coating film met the requirements of graphene materials. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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12 pages, 3515 KiB

Open AccessArticle

Hydrophobic Epoxy Caged Silsesquioxane Film (EP-POSS): Synthesis and Performance Characterization

by Yanhong Fang, Ping Wang, Lifang Sun and Linhong Wang

Nanomaterials 2021, 11(2), 472; https://doi.org/10.3390/nano11020472 - 12 Feb 2021

Cited by 7 | Viewed by 2454

Abstract

Hydrophobic films are widely used in aerospace, military weapons, high-rise building exterior glass, and non-destructive pipeline transportation due to their antifouling and self-cleaning properties. This paper details the successful preparation of hydrophobic epoxy caged sesquioxane (EP-POSS) via two steps of simple organic synthesis, [...] Read more.

Hydrophobic films are widely used in aerospace, military weapons, high-rise building exterior glass, and non-destructive pipeline transportation due to their antifouling and self-cleaning properties. This paper details the successful preparation of hydrophobic epoxy caged sesquioxane (EP-POSS) via two steps of simple organic synthesis, along with studies on the effects of viscosity and reaction time on the reaction. Interestingly, the EP-POSS presented a large contact angle of 125°, indicating its excellent hydrophobicity. The surface micromorphology was observed via FE-SEM (field emission scanning electron microscopy), transmission electron microscopy (TEM), and atomic force microscopy (AFM), and the structural composition and elemental contents were analyzed via X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectrometry (EDS). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) tests showed that EP-POSS had excellent thermal properties, and the first degradation reaction occurred at 354 °C. The mechanical performance and abrasion resistance results demonstrated that EP-POSS could be used in solar panels. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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13 pages, 4553 KiB

Open AccessArticle

Oxygen-Deficient Stannic Oxide/Graphene for Ultrahigh-Performance Supercapacitors and Gas Sensors

by Liyang Lin, Susu Chen, Tao Deng and Wen Zeng

Nanomaterials 2021, 11(2), 372; https://doi.org/10.3390/nano11020372 - 02 Feb 2021

Cited by 12 | Viewed by 2230

Abstract

The metal oxides/graphene nanocomposites have great application prospects in the fields of electrochemical energy storage and gas sensing detection. However, rational synthesis of such materials with good conductivity and electrochemical activity is the topical challenge for high-performance devices. Here, SnO₂/graphene nanocomposite [...] Read more.

The metal oxides/graphene nanocomposites have great application prospects in the fields of electrochemical energy storage and gas sensing detection. However, rational synthesis of such materials with good conductivity and electrochemical activity is the topical challenge for high-performance devices. Here, SnO₂/graphene nanocomposite is taken as a typical example and develops a universal synthesis method that overcome these challenges and prepares the oxygen-deficient SnO₂ hollow nanospheres/graphene (r-SnO₂/GN) nanocomposite with excellent performance for supercapacitors and gas sensors. The electrode r-SnO₂/GN exhibits specific capacitance of 947.4 F g⁻¹ at a current density of 2 mA cm⁻² and of 640.0 F g⁻¹ even at 20 mA cm⁻², showing remarkable rate capability. For gas-sensing application, the sensor r-SnO₂/GN showed good sensitivity (~13.8 under 500 ppm) and short response/recovering time toward methane gas. These performance features make r-SnO₂/GN nanocomposite a promising candidate for high-performance energy storage devices and gas sensors. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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13 pages, 4040 KiB

Open AccessArticle

First-Principle Insight into Ga-Doped MoS₂ for Sensing SO₂, SOF₂ and SO₂F₂

by Wenjun Hou, Hongwan Mi, Ruochen Peng, Shudi Peng, Wen Zeng and Qu Zhou

Nanomaterials 2021, 11(2), 314; https://doi.org/10.3390/nano11020314 - 26 Jan 2021

Cited by 24 | Viewed by 2433

Abstract

First-principle calculations were carried out to simulate the three decomposition gases (SO₂, SOF₂, and SO₂F₂) of sulfur hexafluoride (SF₆) on Ga-doped MoS₂ (Ga-MoS₂) monolayer. Based on density functional theory (DFT), [...] Read more.

First-principle calculations were carried out to simulate the three decomposition gases (SO₂, SOF₂, and SO₂F₂) of sulfur hexafluoride (SF₆) on Ga-doped MoS₂ (Ga-MoS₂) monolayer. Based on density functional theory (DFT), pure MoS₂ and multiple gas molecules (SF₆, SO₂, SOF₂, and SO₂F₂) were built and optimized to the most stable structure. Four types of Ga-doped positions were considered and it was found that Ga dopant preferred to be adsorbed by the top of Mo atom (T_Mo). For the best adsorption effect, two ways of SO₂, SOF₂, and SO₂F₂ to approach the doping model were compared and the most favorable mode was selected. The adsorption parameters of Ga-MoS₂ and intrinsic MoS₂ were calculated to analyze adsorption properties of Ga-MoS₂ towards three gases. These analyses suggested that Ga-MoS₂ could be a good gas-sensing material for SO₂ and SO₂F₂, while it was not suitable for SOF₂ sensing due to its weak adsorption. This work provides a theoretical basis for the development of Ga-MoS₂ materials with the hope that it can be used as a good gas-sensing material for electrical equipment. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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13 pages, 6160 KiB

Open AccessArticle

The Adsorption of H₂ and C₂H₂ on Ge-Doped and Cr-Doped Graphene Structures: A DFT Study

by Yiming Liao, Ruochen Peng, Shudi Peng, Wen Zeng and Qu Zhou

Nanomaterials 2021, 11(1), 231; https://doi.org/10.3390/nano11010231 - 16 Jan 2021

Cited by 23 | Viewed by 2733

Abstract

In order to find an excellent sensing material for dissolved gases in transformer oil, the adsorption structures of intrinsic graphene (IG), Ge-doped graphene (GeG), and Cr-doped graphene (CrG) to H₂ and C₂H₂ gas molecules were built. It was found [...] Read more.

In order to find an excellent sensing material for dissolved gases in transformer oil, the adsorption structures of intrinsic graphene (IG), Ge-doped graphene (GeG), and Cr-doped graphene (CrG) to H₂ and C₂H₂ gas molecules were built. It was found that the doping site right above C atom (T) was the most stable structure by studying three potential doping positions of the Ge and Cr atom on the graphene surface. Then, the structural parameters, density of states, and difference state density of these adsorption systems were calculated and analyzed based on the density functional calculations. The results show that the adsorption properties of GeG and CrG systems for H₂ and C₂H₂ are obviously better than the IG system. Furthermore, by comparing the two doping systems, CrG system exhibits more outstanding adsorption performances to H₂ and C₂H₂, especially for C₂H₂ gas. Finally, the highest adsorption energy (−1.436 eV) and the shortest adsorption distance (1.981 Å) indicate that Cr-doped graphene is promising in the field of C₂H₂ gas-sensing detection. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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12 pages, 3576 KiB

Open AccessArticle

High Sensitivity and High Stability QCM Humidity Sensors Based on Polydopamine Coated Cellulose Nanocrystals/Graphene Oxide Nanocomposite

by Yao Yao, Xianhe Huang, Qiao Chen, Zhen Zhang and Weiwei Ling

Nanomaterials 2020, 10(11), 2210; https://doi.org/10.3390/nano10112210 - 05 Nov 2020

Cited by 30 | Viewed by 3495

Abstract

In this paper, a high sensitivity and high stability quartz crystal microbalance (QCM) humidity sensor using polydopamine (PDA) coated cellulose nanocrystal (CNC)/graphene oxide (GO) (PDA@CNC/GO) nanocomposite as sensitive material is demonstrated. The PDA@CNC was prepared by the self-polymerization action on the surface of [...] Read more.

In this paper, a high sensitivity and high stability quartz crystal microbalance (QCM) humidity sensor using polydopamine (PDA) coated cellulose nanocrystal (CNC)/graphene oxide (GO) (PDA@CNC/GO) nanocomposite as sensitive material is demonstrated. The PDA@CNC was prepared by the self-polymerization action on the surface of CNC, and it acted as filler material to form functional nanocomposite with GO. The material characteristics of PDA@CNC, CNC/GO and PDA@CNC/GO were analyzed by transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The experimental results show that the introduction of PDA@CNC into GO film not only effectively enhanced the sensitivity of GO-based nanocomposite-coated QCM sensor but also significantly maintained high stability in the entire humidity range. The PDA@CNC/GO30-coated QCM humidity sensor exhibited a superior response sensitivity up to 54.66 Hz/% relative humidity (RH), while the change rate of dynamic resistance of the sensor in the humidity range of 11.3–97.3% RH is only 14% that is much smaller than that of CNC/GO-coated QCM. Besides, the effect of the PDA@CNC content on the sensitivity and stability of GO-based nanocomposite-coated QCM humidity was also studied. Moreover, other performances of PDA@CNC/GO-coated QCM humidity sensor, including humidity hysteresis, fast response and recovery and long-term stability, were systematically investigated. This work suggests that PDA@CNC/GO nanocomposite is a promising candidate material for realizing high sensitivity and high stability QCM humidity sensor in the entire humidity detection range. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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15 pages, 5710 KiB

Open AccessFeature PaperArticle

Low Working Temperature of ZnO-MoS₂ Nanocomposites for Delaying Aging with Good Acetylene Gas-Sensing Properties

by Sijie Wang, Weigen Chen, Jian Li, Zihao Song, He Zhang and Wen Zeng

Nanomaterials 2020, 10(10), 1902; https://doi.org/10.3390/nano10101902 - 23 Sep 2020

Cited by 14 | Viewed by 2738

Abstract

The long-term stability and the extension of the use time of gas sensors are one of the current concerns. Lowering the working temperature is one of the most effective methods to delay aging. In this paper, pure MoS₂ and ZnO-MoS₂ nanocomposites [...] Read more.

The long-term stability and the extension of the use time of gas sensors are one of the current concerns. Lowering the working temperature is one of the most effective methods to delay aging. In this paper, pure MoS₂ and ZnO-MoS₂ nanocomposites were successfully prepared by the hydrothermal method, and the morphological characteristics were featured by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Pure MoS₂ and ZnO-MoS₂ nanocomposites, as a comparison, were used to study the aging characteristic. The sensing properties of the fabricated gas sensors with an optimal molar ratio ZnO-MoS₂ (Zn:Mo = 1:2) were recorded, and the results exhibit a high gas-sensing response and good repeatability to the acetylene detection. The working temperature was significantly lower than for pure MoS₂. After aging for 40 days, all the gas-sensing response was relatively attenuated, and pure MoS₂ exhibits a faster decay rate and lower gas-sensing response than nanocomposites. The better gas-sensing characteristic of nanocomposites after aging was possibly attributed to the active interaction between ZnO and MoS₂. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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Review

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37 pages, 8814 KiB

Open AccessReview

Bimetallic Nanocrystals: Structure, Controllable Synthesis and Applications in Catalysis, Energy and Sensing

by Gaojie Li, Wenshuang Zhang, Na Luo, Zhenggang Xue, Qingmin Hu, Wen Zeng and Jiaqiang Xu

Nanomaterials 2021, 11(8), 1926; https://doi.org/10.3390/nano11081926 - 26 Jul 2021

Cited by 34 | Viewed by 4317

Abstract

In recent years, bimetallic nanocrystals have attracted great interest from many researchers. Bimetallic nanocrystals are expected to exhibit improved physical and chemical properties due to the synergistic effect between the two metals, not just a combination of two monometallic properties. More importantly, the [...] Read more.

In recent years, bimetallic nanocrystals have attracted great interest from many researchers. Bimetallic nanocrystals are expected to exhibit improved physical and chemical properties due to the synergistic effect between the two metals, not just a combination of two monometallic properties. More importantly, the properties of bimetallic nanocrystals are significantly affected by their morphology, structure, and atomic arrangement. Reasonable regulation of these parameters of nanocrystals can effectively control their properties and enhance their practicality in a given application. This review summarizes some recent research progress in the controlled synthesis of shape, composition and structure, as well as some important applications of bimetallic nanocrystals. We first give a brief introduction to the development of bimetals, followed by the architectural diversity of bimetallic nanocrystals. The most commonly used and typical synthesis methods are also summarized, and the possible morphologies under different conditions are also discussed. Finally, we discuss the composition-dependent and shape-dependent properties of bimetals in terms of highlighting applications such as catalysis, energy conversion, gas sensing and bio-detection applications. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials and Nanotechnology in China)

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