Enhanced hydrogen gas generation rate by n-GaN photoelectrode with immersed finger-type indium tin oxide ohmic contacts

2011 ◽  
Author(s):  
Shu-Yen Liu ◽  
Jhao-Cheng Ye ◽  
Yu-Chuan Lin ◽  
Kuo-Hua Chang ◽  
Ming-Lun Lee ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ohmic Contacts ◽  
Hydrogen Gas ◽  
Generation Rate ◽  
Gas Generation ◽  
Gas Generation Rate

Improved Hydrogen Gas Generation Rate of n-GaN Photoelectrode with SiO[sub 2] Protection Layer on the Ohmic Contacts from the Electrolyte

2010 ◽  
Vol 157 (2) ◽  
pp. B266 ◽  
Author(s):  
Shu-Yen Liu ◽  
J. K. Sheu ◽  
Chun-Kai Tseng ◽  
Jhao-Cheng Ye ◽  
K. H. Chang ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Hydrogen Gas ◽  
Generation Rate ◽  
Gas Generation ◽  
Protection Layer ◽  
Gas Generation Rate

scholarly journals Hydrogen gas generation using n-GaN photoelectrodes with immersed Indium Tin Oxide ohmic contacts

2011 ◽  
Vol 19 (S6) ◽  
pp. A1196 ◽  
Author(s):  
Shu-Yen Liu ◽  
Yu-Chuan Lin ◽  
Jhao-Cheng Ye ◽  
S. J. Tu ◽  
F. W. Huang ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ohmic Contacts ◽  
Hydrogen Gas ◽  
Gas Generation

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.

Influence of Oxygen Concentration and Alkalinity on the Hydrogen Gas Generation by Corrosion of Carbon Steel

2000 ◽  
Vol 663 ◽  
Author(s):  
A. Fujiwara ◽  
I. Yasutomi ◽  
K. Fukudome ◽  
T. Tateishi ◽  
K. Fujiwara
Keyword(s):  
Carbon Steel ◽  
Oxygen Concentration ◽  
Test System ◽  
Hydrogen Gas ◽  
Localized Corrosion ◽  
Generation Rate ◽  
Passive State ◽  
Corrosion Mechanism ◽  
Gas Generation ◽  
Gas Generation Rate

ABSTRACTA repository for low and intermediate level radioactive wastes will contain a great deal of carbon steel as reinforcement materials and waste containers. These steel components are expected to generate hydrogen gas due to reductive corrosion of carbon steel under repository condition. In this study, we have investigated the influence of the environmental factors such as oxygen concentration and pH in the solution on the rate of the gas generation. This rate was measured with a gas flow type test system under the controlled oxygen concentration, which simulates the redox conditions from initial to final environment in a repository. In addition, the corrosion mechanism was examined through the electrochemical tests.As a result, it has been found that pH in the solution and the oxygen concentration considerably affected the generation rate of hydrogen gas in various way. As to the influence of pH of the solution, it has been found that the gas generation rate increased with the increase of pH between 11.8 and 14. Further, as to the influence of the oxygen concentration, when the oxygen concentration in the blowing nitrogen gas was 2 ppm or more, the gas generation rate increased with the oxygen concentration. This trend was possibly caused by local decrease of pH due to localized corrosion. The gas generation rate was very low when the oxygen concentration was in the passive region. The rate was equal to 0.01 μm/y or less if the corrosion occurs with an equation: 3Fe+4H2O → Fe3O4 + 4H2 ↑ to 0.01 *m imcro;/y (hereafter we call this the equivalent corrosion rate). However the gas generation rate increased when the oxygen concentration was controlled to the extent that sufficient passive film cannot be produced and thus it shifts from passive state to active state.

Gas Generation Behavior of Transuranic Waste Under Disposal Conditions

1999 ◽  
Vol 556 ◽  
Author(s):  
Ryutaro Fujisawa ◽  
Tetsunari Kurashige ◽  
Yusuke Inagaki ◽  
Muneaki Senoo
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Initial Period ◽  
Hydrogen Gas ◽  
Generation Rate ◽  
Gas Generation ◽  
Geological Disposal ◽  
Synthetic Groundwater ◽  
Gas Generation Rate ◽  
Transuranic Waste

AbstractThe generation of hydrogen-gas from metallic waste is an important issue for the safety analysis of geological disposal facilities for transuranic (TRU) radioactive waste in Japan. The objective of this study is to clarify the gas-generation behavior of stainless steel and carbon steel in non-oxidizing alkaline synthetic groundwater (pH 12.8 and 10.5) at 30 °C simulating geological disposal environments. At pH 12.8, the observed gas-generation rate from stainless steel in the initial period of immersion was 1.0 × 102 Nml/m2/y and 1.0 × 10 Nml/m2/y after 200 days (N represents the standard state of gas at 0 °C and 1 atm). At pH 10.5, gas generation was not observed for 60 days in the initial period. At 60 days, the gasgeneration observed was 5.0 × 10 Nml/m2/y. After 250 days, the gas-generation rate approaches zero. At pH 12.8, the observed gas generation rate of carbon steel in the initial period of immersion was 1.5 × 102 Nml/m2/y and the gas generation rate began to decrease after 200 days. After 300 days, it was 25 Nml/m2/y. At pH 10.5, the gas generation rate in the initial period was 5.0 × 102 Nml/m2/y and was 1.0 × 10 Nml/m2/y after 200 days.

scholarly journals Performance of GaN-Based LEDs with Nanopatterned Indium Tin Oxide Electrode

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Zhanxu Chen ◽  
Wenjie Liu ◽  
Wei Wan ◽  
Gengyan Chen ◽  
Yongzhu Chen ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ohmic Contacts ◽  
Three Dimensional ◽  
Light Output ◽  
Light Extraction Efficiency ◽  
Experimental Result ◽  
Indium Tin Oxide Electrode ◽  
Light Emitting ◽  
Ito Electrode

The indium tin oxide (ITO) has been widely applied in light emitting diodes (LEDs) as the transparent current spreading layer. In this work, the performance of GaN-based blue light LEDs with nanopatterned ITO electrode is investigated. Periodic nanopillar ITO arrays are fabricated by inductive coupled plasma etching with the mask of polystyrene nanosphere. The light extraction efficiency (LEE) of LEDs can be improved by nanopatterned ITO ohmic contacts. The light output intensity of the fabricated LEDs with nanopatterned ITO electrode is 17% higher than that of the conventional LEDs at an injection current of 100 mA. Three-dimensional finite difference time domain simulation matches well with the experimental result. This method may serve as a practical approach to improving the LEE of the LEDs.

Development of Corrosion Inhibitors for Absorption Heat Pumps

2002 ◽  
Author(s):  
C. L. Hannon ◽  
J. Gerstmann ◽  
F. B. Mansfeld ◽  
Z. Sun
Keyword(s):  
Water Absorption ◽  
Corrosion Inhibitors ◽  
Earth Metal ◽  
Heat Pumps ◽  
Generation Rate ◽  
Sodium Chromate ◽  
Gas Generation ◽  
Ammonia Water ◽  
Steel Surfaces ◽  
Gas Generation Rate

This paper describes the results of a research project to develop a non-toxic corrosion in hibitor for the protection of carbon steel surfaces of ammonia-water absorption heat pumps through the use of rare earth metal salt (REMS) compounds. Chromate compounds are currently used as corrosion inhibitors in these systems, but are toxic, environmentally harmful, and their use is being phased out. Corrosion concerns in ammonia-water absorption systems are primarily those of non-condensable (NC) gases generated by corrosion reactions impeding the heat and mass transfer processes in the system. The research focused on the development of a dual-protection REMS based strategy of applying a cerium-oxide/hydroxide coating to the metal surface in a process called cerating, in conjunction with a cerium-sulfate solution-based inhibitor. A laboratory test was conducted in test rigs designed to simulate the conditions of temperature and ammonia concentration found in the desorber component of advanced ammonia-water absorption systems. The test compared the NC gas generation rate in a rig with cerated steel surfaces to a rig using sodium chromate as a solution based inhibitor. The cerated test rig demonstrated an NC gas generation rate about 3 times lower than that of the chromate protected rig. Neither rig showed any indications of significant corrosion activity. This work has shown that cerating can provide superior suppression of NC gas generation in ammonia-water absorption systems compared to sodium chromate, in a process that is simple and readily applicable to the commercial manufacture of equipment.

scholarly journals Transparent Ohmic Contacts on p-GaN Using an Indium Tin Oxide Overlayer

2003 ◽  
Vol 0 (1) ◽  
pp. 214-218 ◽  
Author(s):  
Soo Young Kim ◽  
Ho Won Jang ◽  
Jong-Lam Lee
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ohmic Contacts
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