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H2 gas sensor based on PdOx-doped In2O3 nanoparticles synthesized by flame spray pyrolysis
摘要： In this work, 0–1.0 wt% PdOx-doped In2O3 nanoparticles were successfully synthesized by flame spray pyrolysis (FSP) in a single step for the first time and investigated for gas-sensing applications. The sensing films were fabricated by spin coating and tested towards hydrogen (H2) at various temperatures ranging from 150 to 350 °C in dry air. The powder and sensing film properties were analyzed by X-ray analyses, nitrogen adsorption and electron microscopy. The spherical and cubic In2O3 nanoparticles with diameters ranging from 2 to 20 nm were observed with no apparent secondary phase of Pd or PdOx. Detailed analyses suggested that Pd species might be in the form of PdOx crystallites embedded in and on grain boundaries of In2O3 nanoparticles. From gas-sensing measurements, hydrogen-sensing characteristics of In2O3 nanoparticles were significantly improved by PdOx doping particularly at the optimal Pd content of 0.50 wt%. The optimal PdOx-doped In2O3 sensing film showed a high response of 3526 towards 10,000 ppm H2 at the optimal working temperature of 250 °C. In addition, PdOx doped In2O3 sensing films displayed good stability and high H2 selectivity against various toxic and flammable gases including H2S, NO2, C2H4O, C2H4, C2H5OH and C2H2.
关键词： Flame spray pyrolysis,PdOx doped In2O3,H2 sensor,Semiconducting metal oxide
更新于2025-09-23 15:22:29
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Orthogonal gas sensor arrays by chemoresistive material design
摘要： Gas sensor arrays often lack discrimination power to different analytes and robustness to interferants, limiting their success outside of research laboratories. This is primarily due to the widely sensitive (thus weakly-selective) nature of the constituent sensors. Here, the effect of orthogonality on array accuracy and precision by selective sensor design is investigated. Therefore, arrays of (2–5) selective and non-selective sensors are formed by systematically altering array size and composition. Their performance is evaluated with 60 random combinations of ammonia, acetone and ethanol at ppb to low ppm concentrations. Best analyte predictions with high coefficients of determination (R2) of 0.96 for ammonia, 0.99 for acetone and 0.88 for ethanol are obtained with an array featuring high degree of orthogonality. This is achieved by using distinctly selective sensors (Si:MoO3 for ammonia and Si:WO3 for acetone together with Si:SnO2) that improve discrimination power and stability of the regression coefficients. On the other hand, arrays with collinear sensors (Pd:SnO2, Pt:SnO2 and Si:SnO2) hardly improve gas predictions having R2 of 0.01, 0.86 and 0.28 for ammonia, acetone and ethanol, respectively. Sometimes they even exhibited lower coefficient of determination than single sensors as a Si:MoO3 sensor alone predicts ammonia better with a R2 of 0.68.
关键词： Ethanol,WO3,SnO2,Electronic nose,Ammonia,Gas sensor,Acetone,Flame spray pyrolysis,MoO3
更新于2025-09-23 15:21:21
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Dye sensitized solar cells based on titanium dioxide nanoparticles synthesized by flame spray pyrolysis and hydrothermal sol-gel methods: a comparative study on photovoltaic performances
摘要： Synthesis methods, shape and size of the nanocrystalline titanium dioxide (TiO2) are very crucial parameters for the power conversion efficiency of dye sensitized solar cells. In this article, nanoparticles of TiO2 powders have been synthesized via flame spray pyrolysis and hydrothermal sol-gel methods. These powders have been characterized by X-ray diffraction and scanning electron microscopy. In particular, the photovoltaic performances of the dye sensitized solar cells based on TiO2 synthesized by flame spray pyrolysis and hydrothermal sol-gel method have been compared. A commercial dye, N719 and a platinum doped counter electrode have been used for fabricating cells. Furthermore, a standard dye sensitized solar cell device has been fabricated by using a commercial Titania electrode in order to use as a reference cell. As a result, power conversion efficiencies of solar cells (under standard conditions, AM 1.5 G, 100 mW cm?2) have been calculated as 2.44, 3.94, and 7.67 % with TiO2 synthesized via flame spray pyrolysis method, hydrothermal sol-gel method and reference Titania electrode, respectively.
关键词： Sol gel,Flame spray pyrolysis,Dye sensitized solar cells,Hydrothermal method
更新于2025-09-12 10:27:22
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Sensing of Acetone by Al-doped ZnO
摘要： The development of chemoresistive gas sensors for environmental and industrial air monitoring as well as medical breath analysis is investigated. Flame-made ZnO nanoparticles (NPs) doped with 1 at% Aluminum exhibited higher sensing performance (response 245, response time ~ 3 s, and sensitivity 23 ppm-1) than pure ZnO and those made by a hydrothermal method (HT) (56, ~ 12 s, and 4 ppm-1) for detection of 10 ppm acetone. Furthermore, their sensing response of ~10 to 0.1 ppm of acetone at 90% RH is superior to other metal oxide sensors and they feature good acetone selectivity to other compounds (including NH3, isoprene and CO). Characterization by N2 adsorption, X-ray photoelectron and UV-vis spectroscopies reveals that the improved sensing performance of flame-made Al-doped ZnO NPs is associated primarily to a higher density of oxygen vacancies than pure ZnO and all HT-made NPs. This leads to a greater number of adsorbed oxygen ions on the surfaces of Al-doped ZnO NPs, which can react with acetone molecules.
关键词： nanoparticles,flame spray pyrolysis,Al-doped ZnO,acetone,gas sensors
更新于2025-09-10 09:29:36
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Flame spray pyrolysis synthesized gold-loaded titanium dioxide photocatalyst for degradation of Rhodamine B
摘要： Gold-loaded titanium dioxide (Au-loaded TiO2) was synthesized by the flame spray pyrolysis method for using as photocatalyst. The synthesized Au-loaded TiO2 photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic degradation of Rhodamine B (RhB) dye solution over synthesized Au-loaded TiO2 was studied. The concentration of RhB was determined by UV–Vis spectrophotometry. For the photocatalytic activity, it was found that Au(1.00 mol%)-loaded TiO2 was a better photocatalyst than others under the same reaction conditions. The optimal conditions for photocatalytic degradation of RhB were found to be 0.6 g/L of photocatalyst concentration under UV light irradiation (UV–C 254 nm). The highest kinetic rate constant of photocatalyst was 0.0057 min?1 at the optimum conditions and the mechanism of the photocatalytic process had also been discussed.
关键词： Rhodamine B,Flame spray pyrolysis,Au-loaded TiO2,Degradation,Photocatalyst
更新于2025-09-09 09:28:46
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Effect of doping Fe/Cu/Ti on WO <sub/>3</sub> on furfural degradation
摘要： This research improved tungsten oxide catalysts to increase efficiency in photocatalytic degradation of furfural under visible light. The aim of this research was to compare the efficiency of modified tungsten oxide with undoped and commercial tungsten oxide. Tungsten oxide nanoparticles were doped with 3 single metals, which were Fe/Cu/Ti at 1%wt, 2%wt, and 3%wt, synthesized by flame spray pyrolysis technique (FSP) and then characterization by X-Ray Diffraction (XRD), N2 adsorption/desorption (BET surface area analysis), UV-Vis Spectroscopy (UV-Vis). Photocatalytic degradation experiments using doped WO3 were carried out with 5 ppm initial concentration of furfural solution using 0.6 M catalyst concentration under visible light. From the results, FSP-synthesized WO3 has better efficiency in furfural degradation than the commercial WO3. All catalysts have mesoporous structure because an average pore size is in the range of 6-10 nm. Among all synthesized and doped WO3, it can be concluded that 3%wt Fe-doped tungsten oxide provides the highest acceleration rate in photocatalytic degradation of furfural.
关键词： furfural,photocatalytic degradation,flame spray pyrolysis,tungsten oxide,doping
更新于2025-09-04 15:30:14