Room temperature rapid detection of toxic gases is still ambitious for real-time application. Recently, molybdenum disulfide transition dichalcogenides (MoS2 TMDCs) have been considered as a ...promising material for gas sensing application, owing to their high surface-to-volume ratio. However low response and incomplete recovery hinder their performance. In this work, we demonstrate MoS2 and cobalt incorporated MoS2 to enhance the sensing response and rapid recovery. Co-incorporated (7 at%) MoS2 showed 546.6% enhancement in response compared to pristine MoS2 for 100 ppm of NO2 gas at room temperature. The enhanced edge site presents in the Co-incorporated samples was the reason for excellent gas adsorption and increased response towards NO2 gas molecules. The stability analysis showed 70% of stability of a fabricated device. These results address a new pathway for an ideal gas sensor for room temperature application.
•The pristine MoS2 and co-incorporated MoS2 was successfully synthesized by hydrothermal method.•Studying the effect of cobalt incorporation in MoS2 and their gas sensing properties via home-made gas sensing unit.•The 7 at% of Co-incorporated MoS2 sample showed enhanced response of 51.08% in 10 s for 100 ppm of NO2 gas.•The uniqueness of our work is to fabricate room temperature gas sensor with enhanced sensitivity of 546.6%.
Construction of heterojunction photocatalyst with charges separation is essential in photocatalysis for solar energy conversion. In this work, CuO/ZnO nanocomposites were synthesized with different ...Cu/Zn weight percentage. The morphological transformation from hollow dumbbell to nanosheets was observed with change in Cu/Zn percentage. Moreover, the CuO/ZnO nanocomposite shows good adsorption and photocatalytic decomposition capacity for Methylene Blue (MB). The CuO/ZnO nanocomposites improve the transfer and electron and hole pairs separation. Compared to TiO2, the CuO/ZnO nanocomposite with 5 wt% of Cu shows enhanced activity with MB degradation of 96.57% in 25 min. The enhanced performance of nanocomposite was explained by the p–n junction interface which hinders the electron-hole pair recombination.
•The morphology transformation from hollow dumbbell to spindles was observed.•The functional properties of the CuO/ZnO nanocomposite were studied.•The CuO/ZnO hetero-junction improved the separation of photogenerated electrons and holes.•Synergetic interaction of CuO/ZnO was achieved for photocatalytic application.
Regular polymer patterns are formed from casting a dilute polymer solution on a solid substrate. Dissipative structures, e.g., convection patterns, fingering instabilities, and so on, are formed in ...the evaporation process of casting polymer films. Controlled production and manufacturing of patterned polymer films can be achieved when the evaporating solution edge, especially the meniscus region on the casting substrate, is formed under controlled casting conditions. In this report, we describe a computer‐controlled apparatus which has two precisely manipulated sliding glass plates. A narrow, thin liquid film of polymer solution with a receding meniscus is continuously supplied from a small gap between two glass plates (one sliding and the other stationary), and a patterned polymer film is subsequently formed on the stationary substrate from the evaporating solution edge. Several types of polymer patterns from various polymers are reproducibly prepared by changing preparation conditions such as sliding speed and polymer concentration.
A thin liquid film of polymer solution with a receding meniscus is continuously supplied from a narrow gap between two plates, one sliding over the other. Three types of patterned polymer films are formed (the Figure shows parallel stripes) on the lower substrate from the evaporating solution edge.
Low energy density of the supercapacitors is considered as a roadblock for its application in or as a primary power source. While, utilization of high energy density battery-type electrode materials ...in an asymmetrical configuration was expected to resolve this hurdle, however, its inferior rate performance and poor cycling stability hinder the overall device performance. Incomplete utilization of active material at elevated current density was identified as the root for poor rate performance. Herein, we developed a hierarchical NiS microspheres build by the self-assembly of hexagonal nanoplates via trimethylamine (TEA) assisted hydrothermal method. The optimized sample exhibited a superior specific capacitance of 606 C/g at 0.5 A/g. More interestingly, the electrode was able to retain 50% (302 C/g at 20 A/g) of its maximum capacity even when the current density was multiplied 40-fold relative to 18% (50 C/g at 20 A/g) shown by control sample prepared without TEA. Excellent rate performance of the electrode could be attributed to the increment in the electrolyte-accessible surface area by morphological modifications. Owing to its porous nature, optimized sample was able to retain 93% of its original capacity at the end of 2000 continuous cycles of charge-discharge. Furthermore, an asymmetric supercapacitor with NiS-C as the positive electrode and activated carbon as the negative electrode delivered a high energy density of 35.07 Wh/kg at a power density of 0.420 kW/kg within an operating voltage window of 1.5 V.
•Erbium effectively aided the photocatalytic activity under visible light irradiation.•The Er doped mesoporous TiO2 nanospheres exhibited ultra-fast degradation of Rhodamine B within 28 min.•1 mM of ...Er doped TiO2 mesoporous nanospheres showed a best efficiency over pure TiO2.
Semiconductor metal oxides have gained enormous attention due to decomposition of organic pollutant from waste water. Among them TiO2 is one of the most promising photocatalyst with a wide range of applications. It has wide band gap of 3.2 eV which limits its activity to the UV range. Therefore TiO2 (as host matrix) can be doped with a luminescent material to form a phosphorous material which can convert incoming sunlight radiation. One of the interesting luminescent material is Er3+ as it can convert near infrared or visible light to visible and UV light, thus improving the photocatalytic activity of TiO2. In this work, we have synthesized Erbium (Er) doped mesoporous TiO2 spheres by solvothermal method. Effects of Er concentration on the formation and their photocatalytic activity have been investigated. Structural and compositional analysis confirms the presence of Er in the composition. Morphological analysis confirms the formation of mesoporous structure with erbium incorporation on the surface of mesoporous spheres. Elemental mapping confirms the uniform distribution of erbium on the surface of mesoporous structure. Photocatalytic activity of the samples was studied, the samples with 1 mM of Er showed the best photocatalytic activity over the pure TiO2.
Nitrogen dioxide (NO2) is one of the toxic gases produced by chemical industries, power plants, and vehicles. In this work, we demonstrate an inexpensive sensing platform for NO2 detection at room ...temperature (RT-32 °C) based on a charge transfer mechanism. Three-dimensional hierarchical SnS2 and SnS2/mesoporous TiO2 nanocomposites were synthesized via the solvothermal method. SnS2/20 wt% mesoporous TiO2 nanocomposites sample showed 245.4% enhanced response compared to pristine SnS2. The fabricated device exhibits excellent selectivity among all other interfering gases with one-month stability. The rapid response and enhanced response achieved were obtained for the minimum concentration of 2 ppm NO2. The formation of heterojunction between SnS2 and mesoporous TiO2 has a synergetic effect, providing more active sites and porous structures for the detection of NO2 gas molecules.
MoS2 is a layered semiconductor material which has a band gap of 1.9 eV. Owing to its visible light activity, MoS2 has been widely investigated for photocatalytic application. It is well established ...that the photocatalytic activity depends on its structure, morphology, size, etc. In this work, layered MoS2/ZnS were synthesized and the effect of ZnS on the structure and morphology of MoS2/ZnS nanocomposites has been investigated. Structural analysis of the MoS2/ZnS reveals formation of hexagonal and cubic phase of MoS2 and ZnS for all samples. Morphological analyses were performed using FESEM (Field Emission Scanning Electron Microscopy) and HRTEM (High Resolution Transmission Electron Microscopy) revealed the formation of 2D layered MoS2 and MoS2/ZnS nanosheets. XPS analysis confirms the presence of Mo 3d, Zn 2p, and S 2p states in the composition. MoS2/ZnS sample with 0.010 M of ZnS showed the highest efficiency by degrading 99.89% of Methylene Blue (MB) in 32 min. This work can give some perspectives on the construction of noble catalysts for visible-light driven photocatalysis.
•MoS2/ZnS were synthesized by hydrothermal method.•The effect of ZnS on the structure and morphology of MoS2/ZnS has been investigated.•MoS2/ZnS showed enhanced efficiency by degrading 99.89% in 32 min.•The enhanced photocatalytic activity attributed to synergetic interaction and separation of charge carriers.
Hierarchical orderd macroporous TiO2 architecture (HOMTA) was prepared with aid of ethylenediamine (EDA) and investigated the impact of amine molecules on the properties of TiO2 architecture. The ...different variation of amine molecules (EDA) leads to tunning the morphology under hydrothermal approach which is confirmed by FESEM and TEM analysis. The XRD and Raman studies confirms the crystal structure of anatase and brookite phase of TiO2. The surface of the architecture strongly depended on the concentration of EDA which plays a vital role in surface area which is revealed by Brunauer Emmett-Teller (BET) analysis. The obtained HOMTA was employed as photocatalyst and active photoanode in the dye sensitized solar cells (DSSC). The DSSC device exhibits excellent efficiency (η) of 5.27% for the EDA capped TiO2 (S5) which had high surface area (167.11 m2/g) for better dye loading, whereas the lower concentration of EDA capped TiO2 (S1, S2, S3 and S4) resulted the efficiency of 2.14, 3.90, 3.25 and 4.37%, respectively. The efficiency of photocatlysis degradation of the prepared samples (S1, S2, S3, S4 and S5) was 94.8, 90.47, 91.41, 91.32 and 93.75% under light source. The excellent photocatalysis property was achieved by S5 within 6 min due to high surface area which inducing more active site.
Display omitted
•Hierarchical TiO2 macroporous with mesoporous architecture was synthesized by hydrothermal method.•The effect of ethylenediamine (EDA) on the formation and functional properties of the TiO2 architecture was investigated.•The surface of the network strongly depended on the concentration of EDA.
Display omitted
The hybrid of organic conducting polymers and inorganic materials with ultralow thermal conductivity, which is a promising strategy for the realization of polymer based effective ...thermoelectric (TE) applications. In this work, ultrathin layered molybdenum disulphide (MoS2) nanosheets/PANI nanocomposites are prepared by hydrothermal route. The effect of varying PANI wt% in the nanocomposites and its interface effect on thermoelectric properties are well investigated. The successful incorporation of PANI between the MoS2 layers confirmed by high resolution transmission electron microscope (HRTEM). The significantly enhanced potential difference of MoS2/ PANI nanocomposites with increasing PANI content is well clarified by the increased Seebeck value. The variable range hopping property is identified and conductivity is raised up highly due to insertion of PANI in layered van der Waal’s gap of MoS2. The effective interface facilitates charge for fast transport. The reduced thermal conductivity is observed of about 0.248 W*m−1*K−1 for 2.5 wt% addition of PANI. The key factor is that the stability of the sample is improved for MoS2/ PANI nanocomposites than pristine MoS2. Our work paved a new approach to improve TE performance by preparing TE MoS2 material through simple chemical route.
The TiO2 is considered by many as the most versatile material with a very large number of applications in many fields that includes photocatalysis and dye-sensitized solar cell (DSSC). But it is ...active mainly in the UV region of the spectrum due to its large band gap, around 3.2 eV, which causes low photon absorption. This limitation can be overcome by doping TiO2 with a lanthanide which enhances the absorption of visible photons. In this report, we investigated pure mesoporous TiO2 and Gd-doped mesoporous TiO2 spheres to analysis its photocatalytic and energy conversion efficiency. Gadolinium was chosen due to its stable 4f orbitals state of Gd3+ ions. The XRD spectra and Raman spectra analysis confirms the presence of TiO2. It was noted that only anatase was in all the synthesised samples. The morphological analysis confirms FESEM, HRTEM and Element mapping analysis confirms the formation of mesoporous structures with gadolinium incorporated on the mesosphere's surface. The synthesis samples' photocatalytic activity was studied and sample with 1 mmol of Gd was found to perform best among all the samples. A DSSC study was also conduct and Gd-doped TiO2 was found to out-perform the TiO2.
•The mesoporous TiO2 and Gadolinium doped mesoporous TiO2 were synthesis using solvothermal method.•The effects of Gadolinium doping on mesoporous TiO2 has been investigated.•The photocatalytic activity studies showed that sample with 1 mM Gd performed best among all the samples.•The J-V characteristic shows that Gd-doped TiO2 performed better efficiency than pure mesoporous TiO2.
