Facile Preparation of TiO2-SnO2 Catalysts using TiO2 as an Auxiliary for Gas Sensing and Advanced Oxidation Processes

MRS Advances ◽  
2016 ◽  
Vol 1 (46) ◽  
pp. 3157-3162 ◽  
Author(s):  
Ritu Malik ◽  
Vijay K. Tomer ◽  
Surender Duhan ◽  
Pawan S. Rana ◽  
S. P. Nehra

ABSTRACTA facile technique was adopted to synthesize beautiful lilac bush resembling TiO2-SnO2 microflowers aggregates for photodegradation of Congo Red (CR). The TiO2-SnO2 microflowers in the 2-3 μm range with high surface area (80 m2/g), under optimized conditions of catalyst dosage (0.3 g/L), dye concentration (100 ppm) and pH value is 10, exhibit excellent photocatalytic activity under visible light, whereby, 98.3% of the CR aqueous solution was degraded in 40 min of illumination time and also shows good recyclable photocatalytic activities. Further, the gas sensing properties of the as-synthesized material were evaluated towards detection of a variety of volatile organic compounds, such as acetone, methanol, benzene, ammonia, toluene, diethyl ether, and ethanol.

2012 ◽  
Vol 476-478 ◽  
pp. 1075-1078 ◽  
Author(s):  
Yan Wang ◽  
Yu Mei Chen ◽  
Jian Chao Shi ◽  
Jian Liang Cao ◽  
Guang Sun ◽  
...  

Porous α-Fe2O3 nanorods were prepared by the hydrothermal method from FeCl4 and urea without templates. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) analysis techniques. The as-prepared α-Fe2O3 has the porous nanorods structured with the length of about 200 nm, diameter of about 50 nm and high surface area (255.2 m2•g-1). The gas-sensing measurement results demonstrated that the sensor of porous α-Fe2O3 nanorods presented high response to ethanol vapor and which can response to ethanol vapor at low-temperature. Due to the exciting gas-sensing properties, the as-prepared porous α-Fe2O3 nanorods would be an ideal candidate for the application in ethanol sensors.


Author(s):  
Yuanyuan Zhang ◽  
Chi Huang ◽  
Li Sun ◽  
Xueying Wang

Ce4+-doped nanometer ZnO powder was synthesized by so-l gel method. The microstructures and properties of the samples were characterized through XRD, UV-Vis and FTIR. The results indicated that the Ce4+ was successfully incorporated into ZnO, and the diameter of the nanometer was about 10.7nm. It induced the redshifting in the UV-Vis spectra. The photocatalytic activity of the samples was investigated using methylene blue (MB) as the model reaction under irradiation with ultraviolet light. The results showed that the doping of Ce4+ could increase the photocatalytic activities of ZnO nanopowders and that the best molar ratio of Ce4+ was n(Ce)/n(Zn) = 0.05, that the surfactant was sodium dodecyl sulfate, and that the nanometer ZnO was calcinated at 550 ℃ for 3 hours. Meanwhile, it inspected the effect of photocatalytic efficiency through the pH of MB, the amount of catalyst, and illumination time. The experimental results revealed that the initial mass concentration of MB was 10 mg/L, that the pH value was 7-8, that the dosage of Ce4+/ZnO photo-catalyst was 5 g/L, that the UV-irradiation time was 2 h, and that the removal rate of MB reached above 85%. Under the optimized conditions, the degradation rate of real dye wastewater was up to 87.67% and the removal efficiency of COD was 63.5%.


Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3096 ◽  
Author(s):  
Vahid Amiri ◽  
Hossein Roshan ◽  
Ali Mirzaei ◽  
Giovanni Neri ◽  
Ahmad I. Ayesh

Acetone is a well-known volatile organic compound that is widely used in different industrial and domestic areas. However, it can have dangerous effects on human life and health. Thus, the realization of sensitive and selective sensors for recognition of acetone is highly important. Among different gas sensors, resistive gas sensors based on nanostructured metal oxide with high surface area, have been widely reported for successful detection of acetone gas, owing to their high sensitivity, fast dynamics, high stability, and low price. Herein, we discuss different aspects of metal oxide-based acetone gas sensors in pristine, composite, doped, and noble metal functionalized forms. Gas sensing mechanisms are also discussed. This review is an informative document for those who are working in the field of gas sensors.


Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1456
Author(s):  
Yujie Fu ◽  
You Zhang ◽  
Qi Xin ◽  
Zhong Zheng ◽  
Yu Zhang ◽  
...  

Chlorinated volatile organic compounds (CVOCs) are vital environmental concerns due to their low biodegradability and long-term persistence. Catalytic combustion technology is one of the more commonly used technologies for the treatment of CVOCs. Catalysts with high low-temperature activity, superior selectivity of non-toxic products, and resistance to chlorine poisoning are desirable. Here we adopted a plasma treatment method to synthesize a tin-doped titania loaded with ruthenium dioxide (RuO2) catalyst, possessing enhanced activity (T90%, the temperature at which 90% of dichloromethane (DCM) is decomposed, is 262 °C) compared to the catalyst prepared by the conventional calcination method. As revealed by transmission electron microscopy, X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction, the high surface area of the tin-doped titania catalyst and the enhanced dispersion and surface oxidation of RuO2 induced by plasma treatment were found to be the main factors determining excellent catalytic activities.


2013 ◽  
Vol 798-799 ◽  
pp. 1123-1127
Author(s):  
Hua Lei Zhou ◽  
Qiong Qiong Zhu ◽  
Dong Hua Huang

The activated carbon with high surface area was prepared by KOH activation from anthracite and used as adsorbent for removal of Cr (VI) from aqueous solution. The pore structure and surface properties were characterized by N2 adsorption at 77K, transmission electron microscope (TEM) and Fourier transform infrared spectroscopy ( FTIR). Effect of pH and isotherms at different temperature were investigated. Results show that the prepared carbon is a microporous-and mesoporous-adsorbent with developed pore structure and abundant surface oxygen-containing groups. PH value of the solution plays key function on the adsorption. The chemical adsorption dominates the adsorption process. The activated carbon exhibits much higher Cr adsorption capacity than the commercial activated carbon at initial pH of ~3. The equilibrium adsorption data are fitted by both Freundlich model and Langmuir model well.


2014 ◽  
Vol 68 (3) ◽  
pp. 357-362
Author(s):  
Zoran Obrenovic ◽  
Ljubica Nikolic ◽  
Radislav Filipovic ◽  
Marija Milanovic ◽  
Ivan Stijepovic

In the last decade, exploration of transition alumina phases with good adsorption properties has attracted a great research interest from both a fundamental and a practical point of view. The transition phases of alumina are metastable polymorphs of aluminum oxide formed through the thermal dehydration of aluminum trihydroxide and aluminum oxyhydroxide. Powder X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and low-temperature nitrogen absorption studies were employed to trace the formation of the transition phases of alumina. In this work transition alumina powders were synthesized starting from sodium aluminate solution prepared from Bayer liquor. The neutralization of sodium aluminate solution was performed with the use of sulphuric acid, while glucose was added in the starting solution. In this way, the single phase nanocrystalline boehmite was obtained. As-synthesized boehmite powders have high surface area (above 360 m2/g) and the average crystallite size less than 5 nm. The results showed that the properties of the powders (structure, morphology) are strongly influenced by the initial pH value of sodium aluminate solution, as well as by the duration of neutralization step.


2016 ◽  
Vol 70 (6) ◽  
pp. 613-627 ◽  
Author(s):  
Djordje Medarevic ◽  
Dusan Losic ◽  
Svetlana Ibric

Diatoms are widespread unicellular photosynthetic algae that produce unique highly ordered siliceous cell wall, called frustule. Micro- to nanoporous structure with high surface area that can be easily modified, high mechanical resistance, unique optical features (light focusing and luminescence) and biocompatibility make diatom frustule as a suitable raw material for the development of devices such as bio- and gas sensors, microfluidic particle sorting devices, supercapacitors, batteries, solar cells, electroluminescent devices and drug delivery systems. Their wide availability in the form of fossil remains (diatomite or diatomaceous earth) as well as easy cultivation in the artificial conditions further supports use of diatoms in many different fields of application. This review focused on the recent achievements in the diatom bioapplications such as drug delivery, biomolecules immobilization, bio- and gas sensing, since great progress was made in this field over the last several years.


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