Effect of Anodization Bath Chemistry on Photochemical Water Splitting Using Titania Nanotubes

2004 ◽  
Vol 836 ◽  
Author(s):  
Gopal K. Mor ◽  
Oomman K. Varghese ◽  
Maggie Paulose ◽  
Karthik Shankar ◽  
Craig A. Grimes
Keyword(s):  
Water Splitting ◽  
Wall Thickness ◽  
Pore Diameter ◽  
Hydrogen Generation ◽  
Hydrogen Gas ◽  
Photoelectrochemical Cell ◽  
Nanotube Arrays ◽  
Titania Nanotube Arrays ◽  
Variable Wall Thickness ◽  
Variable Wall

ABSTRACTIn this study highly-ordered titania nanotube arrays of variable wall-thickness and length are used to photocleave water under ultraviolet irradiation. We demonstrate that the wall thickness, and length, of the nanotubes can be controlled via anodization bath composition and temperature. The nanotube length and wall thickness are key parameters influencing the magnitude of the photoanodic response and the overall efficiency of the water-splitting reaction. For 22 nm inner-pore diameter nanotube-arrays 6 μm in length, with 9 nm wall thickness, upon 320–400 nm illumination at an intensity of 100 mW/cm2, hydrogen gas was generated at the power-time normalized rate of 51 mL/hr•W at an overall conversion efficiency of 12.5%. To the best of our knowledge, this hydrogen generation rate is the highest reported for a titania-based photoelectrochemical cell.

scholarly journals Extrusion of magnesium alloy hollow profiles with axial variable wall thickness

2019 ◽  
Author(s):  
Maik Negendank ◽  
Vidal Sanabria ◽  
Sören Müller ◽  
W. Reimers
Keyword(s):  
Magnesium Alloy ◽  
Wall Thickness ◽  
Variable Wall Thickness ◽  
Variable Wall

Hydrogen Generation from CDS Modified-Titania Nanotube Arrays

2012 ◽  
Vol 463-464 ◽  
pp. 743-747
Author(s):  
Ygin Chieh Chen ◽  
Jia You Liou ◽  
Wen Jie Lan ◽  
Jyun Yu Chen ◽  
Hong Wen Wang
Keyword(s):  
Catalytic Effect ◽  
Hydrogen Generation ◽  
Nano Particles ◽  
Nanotube Arrays ◽  
Heterogeneous Structure ◽  
Electron Hole ◽  
Titania Nanotube Arrays ◽  
Structures And Properties ◽  
Uv Visible ◽  
Photo Electrode

A heterogeneous structured photo electrode using CDS -modified TiO2nanotube arrays (TNA) was fabricated. The CDS nano particles were precipitated by immersing TNA into NaS and Cd (ClO4)2solution, where the number of immersion gave different amount of CDS precipitates. The effect of CDS on the performance of photochemical cell of TNA was evaluated. FESEM, EDS, XRD and UV-Visible were employed to characterize the structures and properties of CDS -modified TNA heterogeneous structure. The water splitting experiments were carried out using these CDS -modified TNA under standard AM 1.5 solar illumination (100mW/cm2>). An optimum hydrogen generation rate of 20.61μmole/cm2>)h (~0.50 ml/cm2>)h) was obtained. It was considered that the smaller band gap of CDS rendered the electrons a rapid transportation to the TiO2nanotube arrays and the recombination of electron-hole was therefore effectively prevented. In summary, the CDS nano particles were effective in promoting the catalytic effect of TNA for hydrogen production.

Assembling γ-graphyne surrounding TiO2 nanotube arrays: An efficient p-n heterojunction for boosting photoelectrochemical water splitting

2021 ◽  
Author(s):  
Dong Qiu ◽  
Chengli He ◽  
Yuxuan Lu ◽  
Qiaodan Li ◽  
Yang Chen ◽  
...  
Keyword(s):  
Water Splitting ◽  
Charge Separation ◽  
Hydrogen Generation ◽  
Electron Injection ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Photoelectrochemical Water Splitting ◽  
Nanotube Arrays ◽  
Injection Efficiency ◽  
Electron Injection Efficiency

Photoelectrochemical water splitting is an excellent strategy for hydrogen generation, and it is pivotal to develop photoanodes with proficient sunlight harvesting, rapid charge separation, and enhanced electron injection efficiency. In...

scholarly journals Thickness-dependent photoelectrochemical properties of a semitransparent Co3O4 photocathode

2018 ◽  
Vol 9 ◽  
pp. 2432-2442 ◽  
Author(s):  
Malkeshkumar Patel ◽  
Joondong Kim
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Hydrogen Generation ◽  
Hydrogen Gas ◽  
Generation Rate ◽  
Alkaline Electrolyte ◽  
Stoichiometric Ratio ◽  
Gas Generation ◽  
Pec Cells ◽  
Gas Generation Rate

Co3O4 has been widely studied as a catalyst when coupled with a photoactive material during hydrogen production using water splitting. Here, we demonstrate a photoactive spinel Co3O4 electrode grown by the Kirkendall diffusion thermal oxidation of Co nanoparticles. The thickness-dependent structural, physical, optical, and electrical properties of Co3O4 samples are comprehensively studied. Our analysis shows that two bandgaps of 1.5 eV and 2.1 eV coexist with p-type conductivity in porous and semitransparent Co3O4 samples, which exhibit light-induced photocurrent in photoelectrochemical cells (PEC) containing the alkaline electrolyte. The thickness-dependent properties of Co3O4 related to its use as a working electrode in PEC cells are extensively studied and show potential for the application in water oxidation and reduction processes. To demonstrate the stability, an alkaline cell was composed for the water splitting system by using two Co3O4 photoelectrodes. The oxygen gas generation rate was obtained to be 7.17 mL·h−1 cm−1. Meanwhile, hydrogen gas generation rate was almost twice of 14.35 mL·h−1·cm−1 indicating the stoichiometric ratio of 1:2. We propose that a semitransparent Co3O4 photoactive electrode is a prospective candidate for use in PEC cells via heterojunctions for hydrogen generation.

Obtaining Body Parts with Variable Wall Thickness Along the Perimeter

2021 ◽  
pp. 473-479
Author(s):  
Yuliya Bessmertnaya ◽  
Alexander Malyshev ◽  
Vladimir Vikhorev ◽  
Pavel Romanov
Keyword(s):  
Wall Thickness ◽  
Body Parts ◽  
Variable Wall Thickness ◽  
Variable Wall

The Bending of Curved Pipes With Variable Wall Thickness

2003 ◽  
Vol 70 (2) ◽  
pp. 253-259 ◽  
Author(s):  
V. P. Cherniy
Keyword(s):  
Cross Section ◽  
Wall Thickness ◽  
Shell Theory ◽  
Neutral Line ◽  
Radius Of Curvature ◽  
Curved Pipes ◽  
Variable Wall Thickness ◽  
Previous Solution ◽  
Variable Wall ◽  
Thin Shell Theory

A general solution is presented for the in-plane bending of short-radius curved pipes (pipe bends) which have variable wall thickness. Using the elastic thin-shell theory, the actual radius of curvature of the pipe’s longitudinal fibers and displacement of the neutral line of the cross section under bending are taken into account. The pipe’s wall thickness is assumed to vary smoothly along the contour of the pipe’s cross section, and is a function of an angular coordinate. The solution uses the minimization of the total energy, and is compared to our previous solution for curved pipes with constant wall thickness.

Comparison of Three Methods of MOM, MLFMM and PO/MOM for Simulation of Variable Wall Thickness Radome

2011 ◽  
Vol 268-270 ◽  
pp. 946-949
Author(s):  
Lie Zhang ◽  
Juan Zhang ◽  
Peng Fei Du ◽  
Zuo Jun Li ◽  
Zhu Feng Yue
Keyword(s):  
Wall Thickness ◽  
Method Of Moments ◽  
Variable Thickness ◽  
Fast Multipole Method ◽  
Design Concept ◽  
Physical Optics ◽  
Medium Size ◽  
Method Of Moment ◽  
Variable Wall Thickness ◽  
Variable Wall

a Design Concept of Piecewise Variable Wall Thickness of Radome Is Proposed to Simulate the Radome which Has Variable Wall. the Paper Calculates the Far Field of a Medium-Size Radome in the Case of Piecewise Variable Thickness by Three Methods as Follows: Method of Moment (MOM), Multilevel Fast Multipole Method (MLFMM) and Physical Optics& the Method of Moments (PO/MOM) Respectively. after Comparing the Results, we Find that the PO/MOM Method Have the Superiority in Simulation of Radome’s Electromagnetic because it’s More Accuracy and Less Memory Consuming than the other Two Methods. Also it Proves the Feasibility of the Design Concept of Piecewise Variable Thickness for Radome.

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