Effect of Water Content on Structural and Photoelectrochemical Properties of Titania Nanotube Synthesized in Fluoride Ethylene Glycol Electrolyte

2012 ◽  
Vol 501 ◽  
pp. 204-208 ◽  
Author(s):  
Yingchin Lim ◽  
Zulkarnain Zainal ◽  
Mohd Zobir Hussein ◽  
Weetee Tan

In this work, the effect of water content from < 1 to 100 vol% on the electrochemical anodization of titanium in ethylene glycol-based electrolyte was investigated. The samples were characterized using X-ray diffraction (XRD) and their dimensional change was monitored by field emission scanning electron microscopy (FE-SEM). It was found that the microstructure and morphology of TiO2 varies dramatically with the water content. Nanotubes become less ordered with increasing water content up to 50 vol%. At 75 vol% water, only porous structure could be observed. Most importantly, at fixed applied voltage, smoother but relatively longer tubes can be grown with lower water content. Varying water content has no effect on the crystalline phase of the resulted nanotubes. However, the intensity of anatase (101) peak increases with increasing water content, indicating better crystallinity of samples. Nanotubes obtained in 50 vol% water exhibit the highest photoresponse when tested using linear sweep photovoltammetry due to enhanced microstructure and crystallinity.

2010 ◽  
Vol 173 ◽  
pp. 102-105 ◽  
Author(s):  
Khairul Arifah Saharudin ◽  
Srimala Sreekantan

In this paper, anodization of Ti foil was carried out in ethylene glycol (EG) containing 5 wt% NH4F solution and 0 to 1.5 wt% of water at 50 V for 60 min. The pH of the bath was kept constant at ~pH7. The crystal structure was studied by X-Ray Diffraction (XRD) analysis, and the morphology was observed via field emission scanning electron microscopy (FESEM). TiO2 nanotube with aspect ratio of 100 was obtained in EG containing less than 1wt % water. The nanotubes wall was very smooth. Increasing the water content > 1wt % results in short nanotubes of approximately 6.2μm with aspect ratio of 62. As anodized, nanotubes were amorphous and annealed at 400 °C promote 100 % anatase phase. Photocatalytic activity of the nanotubes produced at different water content was also evaluated by the degradation of methyl orange and the detail of the observation was discussed thoroughly in this paper.


POSITRON ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 14
Author(s):  
Suci Aprilia ◽  
Erry Koryanti ◽  
Idha Royani

Telah dilakukan pembuatan molecular imprinted polymer (MIP) nano karbaril dengan metode cooling-heating. Pembuatan MIP nano karbaril bertujuan untuk mendapatkan material sensor yang potensial dalam aplikasinya. Dalam penelitian ini, bahan aktif karbaril di-milling dengan variasi waktu 10 menit dan 15 menit. Pada proses polimerisasi melibatkan templat nano karbaril, methacrylic acid (MAA) sebagai monomer fungsional, ethylene glycol dimathacrylate (EDMA) sebagai crosslinker, benzoil peroksida (BPO) sebagai inisiator, dan acetonitril sebagai pelarut yang disintesis menggunakan metode cooling-heating. Dengan cara yang sama, non-imprinted polymer (NIP) juga dibuat sebagai polimer kontrol.  NIP merupakan polimer yang dibuat dengan komposisi dan cara yang sama dengan MIP, namun tidak ditambahkan nano karbaril sebagai zat aktif. Pembuangan templat pada proses ekstraksi sangat berperan penting untuk menghasilkan material sensor yang baik. MIP, polimer, dan NIP yang dihasilkan di karakterisasi menggunakan Fourier transform infrared (FTIR) dan sampel terbaik dideteksi lebih lanjut dengan uji x-ray diffraction (X-RD), dan scanning electron microscope (SEM). Hasil FTIR menunjukkan bahwa gugus fungsi spesifik nano karbaril pada NIP tidak tampak bila dibandingkan dengan spektra MIP, dan terjadi penurunan persen transmitansi pada polimer dan peningkatan % transmitansi pada MIP. Hal ini menjelaskan bahwa terjadi penurunan konsentrasi nano karbaril pada MIP setelah proses ektraksi. Hasil X-RD menunjukkan ukuran kristal yaitu 9,16 Å. Hasil SEM menunjukkan bahwa jumlah pori tercetak dengan ukuran ≤100 nm yaitu 383 pori.  Data ini mengindikasikan bahwa MIP nano karbaril potensial untuk diaplikasikan sebagai material sensor.


2011 ◽  
Vol 311-313 ◽  
pp. 477-480
Author(s):  
Zhi Ai Yang ◽  
Li Jin Feng ◽  
Xia Wang ◽  
Rong Ma ◽  
Jian Ping Sun ◽  
...  

Subscript textThe Co3O4 nanocubes were synthesized by hydrothermal process. The products are characterized in detail by multiform techniques: scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis. The results show that the products are uniform nanocubes with an average crystallite size about 20-40 nm. Electrocatalytic property of the prepared Co3O4 nanocubes was characterized by linear sweep voltammetry. LSV results indicate that Co3O4 nanocubes exhibit a remarkable electrocatalytic activity for the H2O2 reduction.


2021 ◽  
Vol 19 (1) ◽  
pp. 27-32
Author(s):  
Ida Nur Apriani Apriani ◽  
Jarnuzi Gunlazuardi

Telah dilakukan sintesis fotokatalis N/TiO2 bermofologi nanotube dengan metode anodisasi  menggunakan ammonium nitrat (NH4NO3) sebagai sumber dopan pada berbagai variasi konsentrasi (0,5M , 1M, 2M), dilanjutkan dengan kalisinasi pada suhu 4500C selama 2 jam untuk mendapatkan fasa kristal anatase. Karakterisasi dilakukan menggunakan Scanning Electron Miscroscopy (SEM), Fourier Transform Infra Red (FT-IR), X-ray Diffraction (XRD), dan DRS (Diffused Reflectant Spectrometry) UV-Vis. Pengujian Linear Sweep Voltametri dan Multi Pulse Anperiometri pada fotokatalis­ N/TiO2 telah berhasil diterapkan untuk degradasi senyawa Rhodamin B menggunakan sinar UV maupun sinar tampak. Aplikasi dari uji fotoelektrokatalisis menggunakan sinar tampak untuk N/TiO2-NT memberikan hasil eliminasi sebesar 47,86%, sedangkan bila menggunakan TiO2 nanotube tanpa dopan eleminasi hanya sebesar 25,49%. Hal ini menunjukkan bahwa proses doping yang dilakukan telah berhasil menyisipkan nitrogen kedalam matrik TiO2 nanotube dan memperbaiki kinerja fotokatalisis nya di daerah sinar tampak.


2018 ◽  
Vol 233 (1) ◽  
pp. 105-116
Author(s):  
Christoph Seitz ◽  
Sebastian Werner ◽  
Roland Marschall ◽  
Bernd M. Smarsly

Abstract Copper oxide (CuO) nanofibres are utilised to sense the toxic and abrasive gas hydrogen sulfide (H2S) in the ppm (parts per million) range. The detection by CuO is based on a significant increase in the conductance upon the formation of CuS, and is thereby selective and sensitive towards H2S. Nanofibres outperform thin films of CuO by compensating the volumetric stress which occurs during sensing. Here, sensors are presented exhibiting up to 600 cycles of sensing and regeneration. To get further insights into the degradation of the fibres upon the reaction with H2S the sensors were analysed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), resistance and linear sweep voltammetry (LSV) measurements before and after cycling. SEM and TEM revealed a drastic change in morphology of the CuO fibres resulting in an undefined aggregate of nanoparticles after 600 cycles. Resistance and LSV measurements showed that the contacting and the measurement process itself are crucial factors for optimising long-term use of CuO-based H2S sensors.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


Author(s):  
R. J. Narconis ◽  
G. L. Johnson

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.


Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.


MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.


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