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Spray pyrolysis synthesis of mesoporous TiO2 microspheres and their post modification for improved photocatalytic activity
摘要： Mesoporous TiO2 microspheres were prepared by spray pyrolysis for photocatalysis. Post modification of TiO2 by heat treatment was performed to optimize its photocatalytic performance. First, spherical TiO2 particles with mesoporous structure were synthesized at pyrolysis temperatures of 500, 600, and 700 oC. After characterization by XRD, SEM, and N2 adsorption, a sample prepared at 500 oC was found to possess desirable properties for photocatalytic performance through post-modification. In methylene blue degradation, mesoporous TiO2 microspheres synthesized at 500 oC outperformed other microspheres. Furthermore, samples obtained by spray pyrolysis at 500 oC were calcined at various temperatures as a post-modification process. The sample calcined at 350 oC showed improved photocatalytic activity due to optimal anatase crystallinity and surface area.
关键词： Spray Pyrolysis,MB Degradation,Post Modification,Mesoporous TiO2 Spheres
更新于2025-11-21 10:59:37
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Electrochromic performance of chromium-doped Co3O4 nanocrystalline thin films prepared by nebulizer spray technique
摘要： Pristine and chromium (Cr)-doped tricobalt tetraoxide (Co3O4) thin films were grown on glass and FTO substrates by nebulized spray pyrolysis technique. The structural, optical and electrical properties of the pristine and Cr-doped Co3O4 films were characterized by X-ray diffraction, scanning electron microscopy, Raman, and four-probe method. The chemical environment of the elements present in the films was identified from energy dispersive X-ray analysis and X-ray photoelectron spectroscopy. The effect of chromium doping on optical constants is discussed in detail. The electrochromic studies reveal that better optical modulation (?T = 38.3%) and high coloration efficiency (CE = 47 cm2/C) were obtained for 6 at. % of Cr-doped Co3O4 film. The present work suggests that incorporation of Cr in Co3O4 will enhance its electrochromic performance.
关键词： Nebulized spray pyrolysis,Electrochromism,Cr-doped Cobalt oxide,Optical properties
更新于2025-09-23 15:23:52
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A New Catalyst Ti Doped CdO Thin Film for Non-Enzymatic Hydrogen Peroxide Sensor Application
摘要： A new material, Ti doped CdO (Ti: CdO) semiconductor, is firstly reported by this work for electrochemical non-enzymatic hydrogen peroxide (H2O2) sensor applications which was deposited by a simple, versatile and cost-effective chemical spray pyrolysis method on indium doped tin oxide (ITO) substrate. In the basic studies, first, the withstanding of cubic crystal phase along with worthy crystalline nature is discerned on CdO film after Ti doping, here only the preferentially orientated (200) diffraction plane shifted to (111). Subsequently, the irregular spherically shaped CdO nanoparticles (NPs) morphology changed as nearly uniform size with Ti doping is noticed with respect to thermal pyrolytic decomposition process. The existence of Ti atoms in Ti: CdO film is authentically identified and confirmed using EDX and XPS studies respectively. The absorption and emission properties of CdO and Ti: CdO films are studied and confirmed their narrow band gap nature. Importantly, the Ti: CdO film shows pronounced electrocatalytic activity for the reduction of hydrogen peroxide (H2O2) as compared to pure CdO. Hence, the non-enzymatic electrochemical sensing of Ti: CdO electrode shows a lower detection limit 0.4 μM with the linear range of 10-190 μM which displayed a fast amperometric response for 5 s with sensitivity of 0.27 μA μM-1 cm-2 toward H2O2 detection. This result will boost exploring a new opportunity for the deposition of other metal oxides and semiconductors by using a simple chemical spray pyrolysis method for detection of non-enzymatic H2O2 sensor applications.
关键词： H2O2 sensor,and selectivity,Chemical spray pyrolysis,Ti: CdO thin film
更新于2025-09-23 15:23:52
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Structural, morphological, composition and optical properties of undoped zinc oxide thin films prepared by spray pyrolysis method: effect of solution concentrations
摘要： The aim of this paper is the study of transparent undoped zinc oxide thin films obtained by spray pyrolysis technique on glass substrates heated at 350 °C from 0.1 to 0.4 mol solution concentrations using zinc acetate dehydrate as precursor. The X-ray diffraction patterns and Raman spectrometry with respect to Urbach energy and wurtzite structure, show that the maximum value of the high frequency intensity E2 and the optimal value of the optical gap are obtained at 0.2 mol concentration. Furthermore, an appropriate transparency is obtained and that makes these films suitable for photovoltaic windows layer cells.
关键词： X-ray diffraction,ultraviolet transmission spectroscopy,Raman spectroscopy,spray pyrolysis,undoped zinc oxide
更新于2025-09-23 15:23:52
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Sub-micron features from polymer-derived SiOC via imprint lithography
摘要： Silicon oxycarbide (SiOC) is a unique class of materials with great potential for facile manufacturing of complex shaped high temperature parts and devices. In this study, we examine the characteristics of micron-sized ridge and rod patterns of SiOC created by imprint lithography. Feature fidelity, shape change, and shrinkage are studied as a function of pyrolysis condition and feature size. All the features have acceptable surface fidelity under the pyrolysis conditions studied. However, pronounced rounding and flattening of patterned features are observed as the pyrolysis temperature increases or the feature size decreases. Based on the Kelvin and Gibbs-Thomson equations, we can predict the feature evolution and show that the feature rounding and flattening are due to surface diffusion and evaporation-condensation. As a result, the features also have more linear shrinkage than the bulk.
关键词： Shrinkage,Feature fidelity,Silicon oxycarbide,Rounding,Pyrolysis
更新于2025-09-23 15:23:52
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Photoelectrochemical hydrogen production from water splitting using heterostructured nanowire arrays of Bi2O3/BiAl oxides as a photocathode
摘要： To date, most metal oxide-based photocathodes used in photoelectrochemical cells for water splitting contain copper cations in its composition, which can be reduced to metal Cu under cathodic bias leading to deactivation of the photoelectrode. Here, a Cu-free photocathode composed by a ternary heterostructure of Bi2O3/Al2Bi24O39/Al2Bi48O75 nanowires is reported with a narrow band gap energy (1.83 eV) and suitable conduction band edge potential (?0.98 VRHE) for water reduction to hydrogen. Photoelectrochemical measurements display that the highest photocurrent density of ?4.85 mA cm?2 at 0 VRHE under simulated sunlight is achieved by tuning the Bi:Al molar ratio of photocathode to 21:1. The photocurrent onset potential of the Bi2O3/BiAl oxides photoelectrode was estimated to be 0.57 VRHE at pH 7, which is comparable to that of silicon. Controlled potential photoelectrolysis at 0 VRHE showed a stable photocurrent of about ?2 mA cm?2 for 2 h of continuous operation. The H2 measured at this time was 696 μmol cm?2, which corresponds to a Faradaic efficiency of 93%. Finally, this work gives a new generation of Cu-free photocathodes and demonstrates a promising future of BiAl oxides in constructing photoelectrochemical devices for water splitting.
关键词： Oxides,Solar energy,PEC cells,Water reduction,Spray pyrolysis,Heterojunction
更新于2025-09-23 15:23:52
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Influence of precursor solution concentration on the structural, optical and humidity sensing properties of spray-deposited TiO <sub/>2</sub> thin films
摘要： In the present paper, the influence of precursor concentration on the structural, optical, and humidity sensing properties of spray-deposited titanium dioxide (TiO2) films are investigated. The TiO2 thin films were successfully deposited by spraying different precursor concentrations such as 0.075 M, 0.1 M, and 0.125 M of titanium trichloride solution onto glass substrates. X-ray diffractometry (XRD) studies confirmed the polycrystalline anatase phase of TiO2 with dominant (101) plane. The crystallite size was found to increase with the increase in precursor concentration. The micro-strain and dislocation density in the film was observed to decrease as the crystallite size increased. The UV–vis spectra confirmed the optical absorbance edge of the samples shifted toward lower wavelengths with increased precursor concentration. The humidity sensing properties of the synthesized material were measured by monitoring the change in resistance of the sample with the change in relative humidity. The material synthesized with 0.1 M precursor concentration, by using the spray pyrolysis method, shows good sensitivity and has a response time of 77.5 s and fast recovery time of 3 s.
关键词： electrical,titanium dioxide,structural,gas sensing,spray pyrolysis
更新于2025-09-23 15:23:52
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Effect of substrate temperature on the physical properties of SnS <sub/>2</sub> :Cu thin films deposited by spray pyrolysis
摘要： The main impetus of the present study is to investigate thin films of tin disulfide that have been doped with copper impurities and prepared on glass substrates by using the spray pyrolysis technique. Also, the influence of the substrate temperature on the structural, optical, and electrical properties of these films are investigated. The thin films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical absorption (UV–vis) analyses. The XRD patterns clarify that the thin films possess polycrystalline structures, having a peak associated with the (001) plane of the SnS2 phase. The average crystalline grain sizes were estimated to be within the range 5.7–7.1 nm. The SEM images indicate that the grain size increases from 53 to 114 nm with an increment in the substrate temperature, resulting in an increasing–decreasing trend in the band gap of the thin films. However, the films’ resistance decreases from 92.5 to 0.174 Ω·cm as the substrate temperature increases from 400 to 450 °C. Also, their optical energy band gap depicts an increasing–decreasing trend with the estimated values of 2.81, 3.21, and 3.06 eV at 400, 425, and 450 °C, respectively. The thin films exhibit n-type conductivity.
关键词： polycrystalline,spray pyrolysis,thin film
更新于2025-09-23 15:23:52
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Synthesis of Carbon Nanodots from Cellulose Nanocrystals Oil Palm Empty Fruit by Pyrolysis Method
摘要： Biomass such as cellulose is one of the most common abundant organic materials on the Earth. Biomass has carbon chain that could be an excellent choice for the fabrication of carbon materials. Cellulose nanocrystal is nano-sized cellulose and could become the potential source in fabricating carbon nanodots that are affected by pyrolysis temperature. In fact, the size and temperature are essentially important to synthesize the carbon nanodots. This research is contributed to synthesize this material, and to investigate the effect of temperature. The percentage of cellulose nanocrystals and carbon nanodots obtained are less than 50%. Carbon nanodots are synthesized by pyrolysis method and cellulose nanocrystals are fabricated by membrane method. TEM analysis shows that cellulose nanocrystals are nano-sized. Under UV light source, the samples show fluoroscencing colours i.e. blue to green. From this research it can be concluded that the temperature affects the characteristics of carbon nanodots produced by pyrolysis method.
关键词： Pyrolysis,Cellulose Nanocrystals,Fluorescent,Carbon Nanodots
更新于2025-09-23 15:23:52
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ZnO/porous carbon composite from a mixed-ligand MOF for ultrasensitive electrochemical immunosensing of C-reactive protein
摘要： Carbon-based nano-composite materials obtained via simple thermolysis of metal-organic framework (MOF) have competitive virtues in accordance of layered porosity, controllable morphologies, and easily functionalizing with other metal/metallic oxides or hetero atoms. These make them directly as high activity catalysts or supports for various electrochemical sensor. Herein, we developed a novel ZnO/porous carbon matrix (ZnO/MPC)-based electrochemical immunosensing through thermolysis of a mixed-ligand MOF (Zn-BDC-TED) for real sample analysis of C-reactive protein. The ZnO/MPC and ionic liquid (IL) composite membrane modified electrode displayed prominent conductivity and biocompatibility for ultrasensitive detection of C-reactive protein (CRP). Subsequently, the step-by-step assembly process of the CRP immunosensor was monitored by electrochemical measurements including cyclic voltammogram (CV) and electrochemical impedance spectra (EIS). After the parameter optimization, the differential pulse voltammetry (DPV) response decreased linearly with the logarithm of CRP levels in an extensive range of 0.01–1000 ng·mL?1, and the detection limit was as low as 5.0 pg·mL?1. Meanwhile, the lable-free immunosensor also showed excellent selectivity, reproducibility and stability. We believe that ZnO/MPC composite and many carbon-based nano-composite materials obtained via simple thermolysis of MOF will be a prospective platform for sensitive detecting other biomarkers.
关键词： ZnO/MPC,C-reactive protein,Electrochemical immunosensor,Pyrolysis,Lable-free
更新于2025-09-23 15:22:29