MoS 2 -PVP Nanocomposites Decorated ZnO Microsheets for Efficient Hydrogen Detection
TL;DR: In this article, the authors presented a MoS2/ZnO hybrid exhibiting higher molecular detection at low operating temperature, where the ZnO film was grown using the magnetron sputtering technique, while MoS 2-PVP nanocomposites were synthesized through organic polymer assisted liquid exfoliation process.
Abstract: Over the past several decades, metal oxide based gas sensors are widely used for hydrogen gas sensing applications. However, their poor sensitivity and very high value of operating temperature (> 300 °C) pose a severe threat over hydrogen detection due to its highly flammable nature. In recent years, a few strategies have been explored by the researchers to address these formidable challenges faced by the sensing technology. Here, we present MoS2/ZnO hybrid exhibiting higher molecular detection at low operating temperature. The ZnO film was grown using the magnetron sputtering technique, while MoS2-PVP nanocomposites (MoS2-PVP NCs) were synthesized through organic polymer assisted liquid exfoliation process. We examined the sensing performance of various MoS2/ZnO hybrids prepared by the decoration of different concentration MoS2-PVP NCs over the ZnO surface. The decoration of ZnO film through MoS2-PVP NCs increases the effective surface area and the number of active sites for the hydrogen molecules to get adsorbed, hence improved the surface reactivity to gas molecules. Interestingly, a 5 mg/mL MoS2-PVP NCs decorated ZnO sensor showed an improvement of $\sim 8$ times in sensing response as compared to the pristine ZnO based sensor upon 50 ppm hydrogen exposure. The improvement in sensing ability is primarily ascribed to electronic sensitization and spillover effects. Our results establish that the MoS2/ZnO hybrid exhibit superior hydrogen sensing behavior indicating the prominent role of MoS2-PVP NCs in hydrogen detection.
Citations
More filters
[...]
TL;DR: In this paper , a review article focuses on the recent developments of emerging polymeric/inorganic nanohybrids for sensing various toxic gases including ammonia, hydrogen, nitrogen dioxide, carbon oxides and liquefied petroleum gas.
Abstract: Rapid industrial development, vehicles, domestic activities and mishandling of garbage are the main sources of pollutants, which are destroying the atmosphere. There is a need to continuously monitor these pollutants for the safety of the environment and human beings. Conventional instruments for monitoring of toxic gases are expensive, bigger in size and time-consuming. Hybrid materials containing organic and inorganic components are considered potential candidates for diverse applications, including gas sensing. Gas sensors convert the information regarding the analyte into signals. Various polymeric/inorganic nanohybrids have been used for the sensing of toxic gases. Composites of different polymeric materials like polyaniline (PANI), poly (4-styrene sulfonate) (PSS), poly (3,4-ethylene dioxythiophene) (PEDOT), etc. with various metal/metal oxide nanoparticles have been reported as sensing materials for gas sensors because of their unique redox features, conductivity and facile operation at room temperature. Polymeric nanohybrids showed better performance because of the larger surface area of nanohybrids and the synergistic effect between polymeric and inorganic materials. This review article focuses on the recent developments of emerging polymeric/inorganic nanohybrids for sensing various toxic gases including ammonia, hydrogen, nitrogen dioxide, carbon oxides and liquefied petroleum gas. Advantages, disadvantages, operating conditions and prospects of hybrid composites have also been discussed.
61 citations
[...]
TL;DR: In this article , a WS2-polyvinylpyrrolidone (PVP)/Cu memristor based on monolayer WS2 nanosheets and PVP nanocomposites was fabricated, and the influence of PVP content on the switching behaviors was investigated.
Abstract: Ag/tungsten disulfide (WS2)–polyvinylpyrrolidone (PVP)/Cu memristors based on monolayer WS2 nanosheets and polyvinylpyrrolidone (PVP) nanocomposites were fabricated, and the influence of PVP content on the switching behaviors was investigated. The results indicate that the WS2–PVP based memristors show write-once read-many times (WORM) memory behavior. Remarkable resistive switching results such as a low operating voltage (VSET < 1 V), a high switching ratio (>103), good endurance (>100 cycles), and data retention time (>200 s) are obtained. With the increase in the PVP content, the device VSET gradually increases, and the switching ratio first slightly increases and then remarkably decreases. The double logarithm I–V curves verify that the switching mechanism of the devices is the trap-controlled space charge limited current mechanism, which is explained with the energy band diagram.
5 citations
[...]
TL;DR: In this article , colloidal MoS2 quantum dots (QDs) embedded in an insulating matrix of poly-(4vinylpyridine) (PVP) were used as an active layer to fabricate a RRAM device.
Abstract: Conventional memory technologies are facing enormous problems with downscaling, and are hence unable to fulfill the requirement of big data storage generated by a huge explosion of digital information. A resistive random access memory device (RRAM) is one of the most emerging technologies for next-generation computing data storage owing to its high-density stacking, ultrafast switching speed, high non-volatility, multilevel data storage, low power consumption, and simple device structure. In this work, colloidal MoS2 quantum dots (QDs) embedded in an insulating matrix of poly-(4vinylpyridine) (PVP) were used as an active layer to fabricate a RRAM device. The MoS2 QDs-PVP based RRAM device reveals an excellent nonvolatile resistive switching (RS) behavior with a maximum current on-off ratio (ION/IOFF) of 105. High endurance, long retention time, and successive “write-read-erase-read” cycles indicate high-performance RRAM characteristics. The ultimate power consumption by this RRAM device is considerably low for energy saving. In addition, the MoS2 QDs-PVP based device shows RS behavior even at 130 °C. High ION/IOFF, low operating power, high endurance, long retention time, and excellent stability with temperatures reveal that the MoS2 QDs-PVP based device can be a promising candidate for high-performance low power RRAM devices that can be operated at relatively higher temperatures.
3 citations
[...]
01 Jan 2023-Journal of Materials Chemistry C. Materials for Optical, Magnetic and Electronic Devices
TL;DR: The significance of two-dimensional (2D) materials including graphene, and transition metal dichalcogenides has been escalating in gas sensor technology owing to detection of gases at room temperature (RT) and good performance as discussed by the authors .
Abstract: The significance of two-dimensional (2D) materials including graphene, and transition metal dichalcogenides has been escalating in gas sensor technology owing to detection of gases at room temperature (RT) and good...
1 citations
References
More filters
[...]
TL;DR: This work exemplifies the evolution of structural parameters in layered materials in changing from the three-dimensional to the two-dimensional regime by characterized by Raman spectroscopy.
Abstract: Molybdenum disulfide (MoS2) of single- and few-layer thickness was exfoliated on SiO2/Si substrate and characterized by Raman spectroscopy. The number of S−Mo−S layers of the samples was independently determined by contact-mode atomic force microscopy. Two Raman modes, E12g and A1g, exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the three-dimensional to the two-dimensional regime.
3,533 citations
[...]
TL;DR: A brief review of changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors: chemical components, surface-modification and microstructures of sensing layers, temperature and humidity.
Abstract: Conductometric semiconducting metal oxide gas sensors have been widely used and investigated in the detection of gases. Investigations have indicated that the gas sensing process is strongly related to surface reactions, so one of the important parameters of gas sensors, the sensitivity of the metal oxide based materials, will change with the factors influencing the surface reactions, such as chemical components, surface-modification and microstructures of sensing layers, temperature and humidity. In this brief review, attention will be focused on changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors mentioned above.
1,725 citations
[...]
TL;DR: In this article, the state of the art in the field of experimental techniques possible to be applied to the study of conductometric gas sensors based on semiconducting metal oxides is reviewed.
Abstract: The paper critically reviews the state of the art in the field of experimental techniques possible to be applied to the study of conductometric gas sensors based on semiconducting metal oxides. The used assessment criteria are subordinated to the proposed R&D approach, which focuses on the study, and subsequent modelling, of sensors’ performance in realistic operation conditions by means of a combination of phenomenological and spectroscopic techniques. With this viewpoint, the paper presents both the to-date achievements and shortcomings of different experimental techniques, describes – by using selected examples – how the proposed approach can be used and proposes a set of objectives for the near future.
1,252 citations
[...]
TL;DR: Pd-functionalized nanostructures exhibited a dramatic improvement in sensitivity toward oxygen and hydrogen due to the enhanced catalytic dissociation of the molecular adsorbate on the Pd nanoparticle surfaces and the subsequent diffusion of the resultant atomic species to the oxide surface.
Abstract: The sensing ability of individual SnO2 nanowires and nanobelts configured as gas sensors was measured before and after functionalization with Pd catalyst particles. In situ deposition of Pd in the same reaction chamber in which the sensing measurements were carried out ensured that the observed modification in behavior was due to the Pd functionalization rather than the variation in properties from one nanowire to another. Changes in the conductance in the early stages of metal deposition (i.e., before metal percolation) indicated that the Pd nanoparticles on the nanowire surface created Schottky barrier-type junctions resulting in the formation of electron depletion regions within the nanowire, constricting the effective conduction channel and reducing the conductance. Pd-functionalized nanostructures exhibited a dramatic improvement in sensitivity toward oxygen and hydrogen due to the enhanced catalytic dissociation of the molecular adsorbate on the Pd nanoparticle surfaces and the subsequent diffusion ...
1,233 citations