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Advanced polymeric/inorganic nanohybrids: An integrated platform for gas sensing applications.

NO2 is an oxidizing gas, which is considered to be the most dangerous and most toxic gas that should be controlled. Because of the advantages of high sensitivity, selectivity, stability and fast response/recovery speed, the chemical resistance sensor is used as a NO2 gas sensor. This article reviews the NO2 gas sensor based on metal oxides. Firstly, the hazards of NO2 and the major disadvantages of chemiresistive sensors based on metal oxides were discussed. Then, different sensitive materials of chemical resistance sensors were discussed, including metal oxides (MO), conductive polymers and carbon-based materials. Finally, the NO2 gas sensors based on metal oxide (including ZnO, NiO, CuO, SnO2, WO3) were discussed from the aspects of morphology, preparation method, modification, doping and composite. 

Metal Oxide Gas Sensors For Detecting NO2 in Industrial Exhaust Gas: Recent Developments

Adsorption behaviour of hexagonal boron nitride nanosheets towards cationic, anionic and neutral dyes: Insights from first principle studies

Experimental and theoretical analysis of simultaneous removal of methylene blue and tetracycline using boron nitride nanosheets as adsorbent

Experimental and Theoretical Analysis of Simultaneous Removal of Methylene Blue and Tetracycline using Boron Nitride Nanosheets as Adsorbents

In this work, we report unique hybrid composite film fabricated with the amalgamation of metal, semiconductor and polymers for hydrogen sensing application at room temperature. Fabrication of a novel nanocomposite film based on tin oxide (SnO2) nanosheets with polyaniline (PANI) doped with palladium (Pd) is performed using the hydrothermal synthesis technique. Functional aspects of the fabricated films are investigated with XRD, Raman spectra, FESEM, and FTIR spectral analysis. Interactions of the H2 gas molecules with SnO2, SnO2-Pd, PANI, PANI-SnO2, PANI-SnO2-Pd nanocomposite are also theoretically studied. Using first-principles density functional theory, the effects of gas adsorption on the electronic and transport properties of the sensor are examined. The computations show that the sensitivity of the SnO2 to the H2 gas molecules is considerably improved after hybridisation with Pd and, the sensitivity of the PANI to the H2gas molecules is considerably improved after hybridisation with SnO2.Gas sensing characteristics of fabricated films of SnO2, PANI and composite of SnO2/PANI/Pd are also experimentally investigated at room temperature with varying concentration level ranging from 50 to 400 ppm. The highest sensitivity among all the films at room temperature has been observed as ~540% for the SnO2/Pd film at 0.4% of the target gas and performance factor (the ratio of response percentage to total cycle time) is evaluated highest in Pd doped PANI-SnO2 film. Our results reveal the promising future of SnO2, PANI and Pd associated hybrid films in the development of ultra-high sensitive gas sensors.

Room temperature hydrogen sensing with Polyaniline/SnO2/Pd Nanocomposites

In the present work, we report an excellent gas sensing performance of the unique nanocomposite films prepared with the help of different materials such as semiconductor metal-oxide, polymer and metal for carbon monoxide gas sensing at ambient temperature. The fabrication of SnO2/PANI/Pd nanocomposite film was performed using the hydrothermal route. The fabricated films were characterized with various analytical techniques such as X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), and Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) etc. Furthermore, DFT results are used to examine the transport and electronic properties of all prepared films. The computing results show that after hybridizing with Pd and SnO2, the response of the fabricated SnO2 and polyaniline (PANI) films to CO gas molecules is considerably improved. At room temperature, sensing characterization of the fabricated sensing films was carried out by using target gas concentrations with varying ppm level of 50–300. At ambient temperature, the SnO2/PANI/Pd film has the maximum sensitivity ~ 400.8% out of all the fabricated films at 0.3% of the target gas. Our findings show that SnO2, SnO2/Pd, PANI, and SnO2/PANI/Pd composite sensing films have a bright future in the gas sensing application with incredibly-higher sensitivity towards CO gas.

Highly sensitive, ambient temperature CO sensor using tin oxide based composites

The adsorption characteristics of H2 molecules on the surface of Pd-doped and Pd-decorated graphene (G) have been investigated using density functional theory (DFT) calculations to explore the sensing capabilities of Pd-doped/decorated graphene. In this analysis, electrostatic potential, atomic charge distribution, 2D and 3D electron density contouring, and electron localization function projection, were investigated. Studies have demonstrated the sensing potential of both Pd-doped and Pd-decorated graphene to H2 molecules and have found that the gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), i.e., the HOMO-LUMO gap (HLG), decreases to 0.488 eV and 0.477eV for Pd-doped and Pd-decorated graphene, respectively. When H2 is adsorbed on these structures, electrical conductivity increases for both conditions. Furthermore, chemical activity and electrical conductivity are higher for Pd-decorated G than Pd-doped G, whereas the charge transfer of Pd-doped graphene is far better than that of Pd-decorated graphene. Also, studies have shown that the adsorption energy of Pd-doped graphene (−4.3 eV) is lower than that of Pd-decorated graphene (−0.44 eV); a finding attributable to the fact that the recovery time for Pd-decorated graphene is lower compared to Pd-doped graphene. Therefore, the present analysis confirms that Pd-decorated graphene has a better H2 gas sensing platform than Pd-doped graphene and, as such, may assist the development of nanosensors in the future.

Palladium-Functionalized Graphene for Hydrogen Sensing Performance: Theoretical Studies

Over the last few years, the microfluidics phenomenon coupled with the Internet of Things (IoT) using innovative nano-functional materials has been recognized as a sustainable and economical tool for point-of-care testing (POCT) of various pathogens influencing human health. The sensors based on these phenomena aim to be designed for cost-effectiveness, make it handy, environment-friendly, and get an accurate, easy, and rapid response. Considering the burgeoning importance of analytical devices in the healthcare domain, this review paper is based on the gist of sensing aspects of the microfabricated paper-based analytical devices (μPADs). The article discusses the various used design methodologies and fabrication approaches and elucidates the recently reported surface modification strategies, detection mechanisms viz., colorimetric, electrochemical, fluorescence, electrochemiluminescence, etc. In a nutshell, this article summarizes the state-of-the-art research work carried out over the nano functionalized paper-based analytical devices and associated challenges/solutions in the point of care testing domain.

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Nano-functionalized paper-based IoT enabled devices for point-of-care testing: a review

Significant growth has been observed in the research domain of dye-sensitized solar cells (DSSCs) due to the simplicity in its manufacturing, low cost, and high-energy conversion efficiency. The electrolytes in DSSCs play an important role in determining the photovoltaic performance of the DSSCs, e.g., volatile liquid electrolytes suffer from poor thermal stability. Although low volatility liquid electrolytes and solid polymer electrolytes circumvent the stability issues, gel polymer electrolytes with high ionic conductivity and enduring stability are stimulating substitutes for liquid electrolytes in DSSC. In this review paper, the advantages of gel polymer electrolytes (GPEs) are discussed along with other types of electrolytes, e.g., solid polymer electrolytes and p-type semiconductor-based electrolytes. The benefits of incorporating ionic liquids into GPEs are highlighted in conjunction with the factors that affect the ionic conductivity of GPEs. The strategies on the improvement of the properties of DSSCs based on GPE are also presented.

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Vinay Kishnani

Papers

Room temperature hydrogen sensing with Polyaniline/SnO2/Pd Nanocomposites

Highly sensitive, ambient temperature CO sensor using tin oxide based composites

Palladium-Functionalized Graphene for Hydrogen Sensing Performance: Theoretical Studies

Nano-functionalized paper-based IoT enabled devices for point-of-care testing: a review

A Review on Gel Polymer Electrolytes for Dye-Sensitized Solar Cells