scholarly journals Photoelectrochemical properties of N-doped self-organized titania nanotube layers with different thicknesses

2006 ◽  
Vol 21 (11) ◽  
pp. 2824-2828 ◽  
Author(s):  
J.M. Macak ◽  
A. Ghicov ◽  
R. Hahn ◽  
H. Tsuchiya ◽  
P. Schmuki
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Electrochemical Anodization ◽  
Tube Length ◽  
Ammonia Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Organized ◽  
Structure Morphology ◽  
N Doping

The present work reports nitrogen doping of self-organized TiO2 nanotubular layers. Different thicknesses of the nanotubular layer architecture were formed by electrochemical anodization of Ti in different fluoride-containing electrolytes; tube lengths were 500 nm, 2.5 μm, and 6.1 μm. As-formed nanotube layers were annealed to an anatase structure and treated in ammonia environment at 550 °C to achieve nitrogen doping. The crystal structure, morphology, composition and photoresponse of the N-doped were characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and photoelectrochemical measurements. Results clearly show that successful N-doping of the TiO2 nanotubular layers can be achieved upon ammonia treatment. The magnitude of the photoresponse in ultraviolet and visible light is strongly dependent on the thicknesses of the layers. This effect is ascribed to recombination effects along the tube length.

ETHANOL SENSOR OF CdO/Al2O3/CeO2 OBTAINED FROM Ce-DOPED LAYERED DOUBLE HYDROXIDES WITH HIGH RESPONSE AND SELECTIVITY

2013 ◽  
Vol 06 (03) ◽  
pp. 1350035 ◽  
Author(s):  
DONGMEI XU ◽  
MEIYU GUAN ◽  
QINGHONG XU ◽  
YING GUO ◽  
YAO WANG
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Oxides ◽  
Structure Morphology ◽  
Ft Ir ◽  
Ethanol Sensing ◽  
Double Hydroxide ◽  
Double Hydroxides

In this paper, Ce -doped CdAl layered double hydroxide (LDH) was first synthesized and the derivative CdO/Al2O3/CeO2 composite oxide was prepared by calcining Ce -doped CdAl LDH. The structure, morphology and chemical state of the Ce doped CdAl LDH and CdO/Al2O3/CeO2 were also investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), solid state nuclear magnetic resonance (SSNMR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing properties of CdO/Al2O3/CeO2 to ethanol were further studied and compared with CdO/Al2O3 prepared from CdAl LDH, CeO2 powder as well as the calcined Ce salt. It turns out that CdO/Al2O3/CeO2 sensor shows best performance in ethanol response. Besides, CdO/Al2O3/CeO2 possesses short response/recovery time (12/72 s) as well as remarkable selectivity in ethanol sensing, which means composite oxides prepared from LDH are very promising in gas sensing application.

Nitrogen-Doping Induced Optical Bandgap Widening of P-Type Cu2O Flms

2009 ◽  
Vol 1217 ◽  
Author(s):  
Yoshitaka Nakano ◽  
Shu Saeki ◽  
Takeshi Morikawa
Keyword(s):  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Optical Bandgap ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
N Doping ◽  
Hall Effect Measurements ◽  
Optical Bandgap Energy ◽  
P Type

AbstractWe have investigated the effect of N doping into Cu2O films deposited by reactive magnetron sputtering. With increasing N-doping concentration up to 3 at.%, the optical bandgap energy is enlarged from ˜2.1 to ˜2.5 eV with retaining p-type conductivity as determined by optical absorption and Hall-effect measurements. Additionally, photoelectron spectroscopy in air measurements shows an increase in the valence and conduction band shifts with N doping. These experimental results demonstrate possible optical bandgap widening of p-type N-doped Cu2O films, which is a phenomenon that is probably associated with significant structural changes induced by N doping, as suggested from x-ray diffraction measurements.

Reduced electrical resistivity of reaction-sintered SiC by nitrogen doping

2008 ◽  
Vol 23 (4) ◽  
pp. 1020-1025 ◽  
Author(s):  
Young-Sam Jeon ◽  
Hyunho Shin ◽  
Young-Hyun Lee ◽  
Sang-Won Kang
Keyword(s):  
Heat Treatment ◽  
Electrical Resistivity ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Nitrogen Atmosphere ◽  
X Ray Diffraction ◽  
Post Heat Treatment ◽  
X Ray ◽  
Sic Particles ◽  
Transmission Electron

A post heat treatment of reaction-sintered SiC at 1700 °C in nitrogen atmosphere significantly reduced electrical resistivity. A trace of insulating Si3N4 phase was detected via nitrogen heat treatment in high-resolution transmission electron microscopy observation; however, based on x-ray photoelectron spectroscopy, the evidence of nitrogen doping into SiC lattice has been claimed as the mechanism to the decreased resistivity. The increase of the total volume of SiC was apparent in x-ray diffraction during the nitrogen heat treatment, which was interpreted to stem from the growth of the nitrogen-doped intergranular SiC particles and surface doping of the primary SiC to reduce the contact resistance between the primary SiC particles.

scholarly journals Novel, Simple and Low-Cost Preparation of Ba-Modified TiO2 Nanotubes for Diclofenac Degradation under UV/Vis Radiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2714
Author(s):  
Mario Bohač ◽  
Tihana Čižmar ◽  
Vedran Kojić ◽  
Jan Marčec ◽  
Krunoslav Juraić ◽  
...  
Keyword(s):  
Tio2 Nanotubes ◽  
Low Cost ◽  
Electrochemical Anodization ◽  
Oh Radicals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Titanium Thin Films ◽  
Current Densities ◽  
Photogenerated Charge Separation

A novel low-cost synthesis of barium-modified TiO2 nanotube (TNT) arrays was used to obtain an immobilized photocatalyst for degradation of diclofenac. TNT arrays were prepared by electrochemical anodization of titanium thin films deposited on fluorine-doped tin oxide (FTO) coated glass by magnetron sputtering, ensuring transparency and immobilization of the nanotubes. The Ba-modifications were obtained by annealing solutions of Ba(OH)2 spin coated on top of TNT. Three different concentrations of Ba(OH)2 were used (12.5 mM, 25 mM and 50 mM). The crystalline structure, morphology and presence of Ba were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Ba-modified TiO2 nanotubes (BTNT) were tested for photocatalytic degradation of diclofenac under UV/Vis radiation and it was proven that all of the Ba-modified samples showed an increase in photocatalytic activity with respect to the unmodified TNTs. The most efficient photocatalyst was the sample prepared with 25 mM Ba(OH)2 which showed 90% diclofenac degradation after 60 min. This result was in agreement with cyclic voltammetry measurements that showed the largest increase in photo-oxidation current densities for the same sample due to the increased generation of •OH radicals obtained by a more efficient photogenerated charge separation.

scholarly journals The Spinning Voltage Influence on the Growth of ZnO-rGO Nanorods for Photocatalytic Degradation of Methyl Orange Dye

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 660 ◽  
Author(s):  
Pierre G. Ramos ◽  
Clemente Luyo ◽  
Luis A. Sánchez ◽  
Enrique D. Gomez ◽  
Juan M. Rodriguez
Keyword(s):  
Methyl Orange ◽  
Photoelectron Spectroscopy ◽  
Analytical Techniques ◽  
Electrospun Nanofibers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Reduced Graphene ◽  
Structure Morphology ◽  
Seed Layers

In this work, well-designed zinc oxide-reduced graphene oxide (ZnO-rGO) nanorods (NRs) were synthesized by a hydrothermal method using electrospun ZnO-rGO seed layers. The ZnO-rGO seed layers were fabricated on fluorine-doped tin oxide (FTO) glass substrates through calcined of electrospun nanofibers at 400 °C in the air for 1 h. The nanofibers were prepared by electrospinning different spinning voltages and a spinning solution containing zinc acetate, polyvinyl pyrrolidone, and 0.2 wt% rGO. From a detailed characterization using various analytical techniques, for instance, X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS), the dependence of the structure, morphology, and optical properties of the ZnO-rGO NRs was demonstrated. The photocatalytic activities of ZnO-rGO nanorods were evaluated through the degradation of dye methyl orange (MO). The results show that the change of spinning voltages and the coupling of rGO with ZnO improved photodecomposition efficiency as compared to pure ZnO. The highest photocatalytic efficiency was obtained for the ZnO-rGO NRs prepared with a spinning voltage of 40 kV.

scholarly journals Fe + NNoncompensated Codoping TiO2Nanowires: The Enhanced Visible Light Photocatalytic Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zhongpo Zhou ◽  
Haiying Wang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Absorption Enhancement ◽  
Thermal Method ◽  
X Ray Diffraction ◽  
Activity Increase ◽  
X Ray ◽  
Visible Light Range

TheFe + Ncodoped nanowire samples are prepared by hydro-thermal method and annealed in NH3atmosphere. The XRD (X-ray diffraction), SEM (Scanning electron microscope), UV-vis absorption spectroscopy, and BET (Brunauer, Emmett, and Teller) results indicate that the samples are pure anatase nanowires. TheFe + Ncodoped samples have the highest specific surface area, the largest red-shift, and the largest absorption enhancement in the visible light range compared with Fe doped, N doped, and undoped nanowires. The measurements of XPS (X-ray photoelectron spectroscopy) show that N content ofFe + Ncodoped TiO2is about two times as large as that of the N doped TiO2. It is assumed that nitrogen doping plays a very important role for the photocatalytic activity increase and hence theFe + Ncodoped nanowire TiO2shows the most effective photocatalytic activity under the visible light irradiation.

H2S Sensing Properties of Added Copper Oxide in WO3

2013 ◽  
Vol 543 ◽  
pp. 145-149 ◽  
Author(s):  
Rasoul Nowrouzi ◽  
Fatemeh Razi Astaraei ◽  
Shima Kashani ◽  
Azam Iraji Zad
Keyword(s):  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Recovery Time ◽  
Gas Detection ◽  
X Ray Diffraction ◽  
Pure Tungsten ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Structure Morphology ◽  
Scanning Electron

We study Hydrogen sulfide gas detection properties of pure and 1% copper oxide added WO3 thin films. The spin coated deposits on alumina substrates were annealed at 500 C for 1 hour in order to improve the crystallinity of the films. The sensitivity of pure tungsten oxide is poor even at temperatures of about 100 C but the doped samples exhibit good response to H2S gas. Our data show sensitivity of about 1500 in 10 ppm diluted gas in air at 100 C. The films are sensitive to the gas even at 250 ppb (sensitivity about 2) H2S concentration at 100 C but with rather long recovery time. Crystal structure, morphology and chemical composition of samples were studied by X-Ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. We suggest that Cu2O dopants dissociate H2S molecules and spillover of the hydrogen atoms onto the cracked WO3 surface. The reaction of dissociated H2S with adsorbed oxygen is the main reason for reduction of resistivity.

INFLUENCE OF SUBSTRATE TEMPERATURE ON THE COMPOSITION, ELECTRICAL RESISTIVITY AND INFRARED EMISSIVITY OF PtOx FILMS

2019 ◽  
Vol 26 (09) ◽  
pp. 1950056
Author(s):  
WENBO KANG ◽  
DONGMEI ZHU ◽  
XIAOKE LU ◽  
ZHIBIN HUANG ◽  
WANCHENG ZHOU ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Substrate Temperature ◽  
Photoelectron Spectroscopy ◽  
Grazing Incidence ◽  
Infrared Emissivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Influence Of Substrate ◽  
Substrate Temperatures

PtOx films were deposited by direct current (DC) reactive magnetron sputtering in Ar/O2 mixture atmosphere at substrate temperatures ranging from 200∘C to 400∘C. The influence of substrate temperature on the structure, morphology, composition, electrical resistivity and infrared emissivity of PtOx films was studied. The X-ray photoelectron spectroscopy (XPS) and grazing incidence X-ray diffraction (GIXRD) results revealed that the as-deposited amorphous PtOx films were mainly composed of PtO and PtO2 phases. It was found that with the increase in the substrate temperature, the proportion of PtO phase in the films increased, while the electrical resistivity and infrared emissivity of the films decreased with the increasing substrate temperature.

scholarly journals Synthesis of CuO/Co3O4Coaxial Heterostructures for Efficient and Recycling Photodegradation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
R. X. Chen ◽  
S. L. Zhu ◽  
J. Mao ◽  
Z. D. Cui ◽  
X. J. Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Wire Mesh ◽  
X Ray Diffraction ◽  
Full Spectrum ◽  
Composite Photocatalyst ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Coaxial Heterostructure

The highly efficient CuO/Co3O4composite photocatalyst with different morphologies has been synthesized directly on Cu wire mesh by controlling the composition of cobalt-containing solid precursors via a simple hydrothermal method. The structure morphology and composition of the composite photocatalyst have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance spectra. The photocatalytic result shows that the CuO/Co3O4coaxial heterostructure is easy to recycle and exhibit enhanced photodegradation activity for methylene blue compared to single CuO nanorod arrays under full spectrum solar light irradiation. The enhanced photocatalytic efficiency of the composite could be ascribed to the synergistic effect of CuO and Co3O4. This study provides a general and effective method in the fabrication of 1D composition NRs with sound heterojunctions that show enhancement of photocatalytic performance and facility of recycling.

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