Development of Hybrid WO3-TiO2 Nanotubes for Solar Hydrogen Generation via Water Electrolysis

2014 ◽  
Vol 925 ◽  
pp. 474-478
Author(s):  
Chin Wei Lai ◽  
Kung Shiuh Lau
Keyword(s):  
High Efficiency ◽  
Hydrogen Generation ◽  
Rf Sputtering ◽  
Light Response ◽  
Water Electrolysis ◽  
Ammonium Fluoride ◽  
Energy System ◽  
Photocurrent Density ◽  
High Energy ◽  
Solar Hydrogen

Solar hydrogen (H2) generation from water electrolysis is a key target for the development of sustainable hydrogen economy for future energy system. The formation of self-organized and highly ordered titania (TiO2) nanotubes is essential for high efficiency in photoelectrochemical (PEC) water electrolysis application. Based on our preliminary studies, highly ordered TiO2nanotubes were successfully synthesized through anodization of titanium (Ti) foil in ethylene glycol (EG) containing 5 wt% of ammonium fluoride (NH4F) and 5 wt% of hydrogen peroxide (H2O2) at 60 V for 1 h. However, an obvious hindrance to the widespread use of TiO2nanotubes as a photoelectrode in PEC water electrolysis system is its poor visible light response and rapid recombination of photo-induced electron/hole pairs. Thus, continuous efforts have been exerted to improve the efficiency of PEC water electrolysis by incorporating an optimum content of W6+species into TiO2nanotubes. In the present study, a practical technique of radio frequency (RF) sputtering was selected to incorporate W6+species into TiO2lattice. It was found that TiO2nanotubes sputtered at high energy of 50 W for 30 sec demonstrated a maximum photocurrent density of ~ 2.4 mA/cm2with photoconversion efficiency ~ 6 %.

Synthesis and Structure of Titania Nanotubes For Hydrogen Generation

2013 ◽  
Vol 741 ◽  
pp. 84-89 ◽  
Author(s):  
Sangworn Wantawee ◽  
Pacharee Krongkitsiri ◽  
Tippawan Saipin ◽  
Buagun Samran ◽  
Udom Tipparach
Keyword(s):  
Oxalic Acid ◽  
Hydrogen Generation ◽  
Ammonium Fluoride ◽  
Photocurrent Density ◽  
Sodium Sulphate ◽  
Titania Nanotubes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dc Power ◽  
Anodic Voltage

Titania nanotubes (TiO2NTs) working electrodes for hydrogen production by photoelectrocatalytic water splitting were synthesized by means of anodization method. The electrolytes were the mixtures of oxalic acid (H2C2O4), ammonium fluoride (NH4F), and sodium sulphate (VI) (Na2SO4) with different pHs. A constant dc power supply at 20 V was used as anodic voltage. The samples were annealed at 450 °C for 2 hrs. Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) were used to characterized TiO2NTs microstructure. TiO2NTs with diameter of 100 nm were obtained when pH 3 electrolyte consisting of 0.08 M oxalic acid, 0.5 wt% NH4F, and 1.0 wt% Na2SO4was used. Without external applied potential, the maximum photocurrent density was 2.8 mA/cm2under illumination of 100 mW/cm2. Hydrogen was generated at an overall photoconversion efficiency of 3.4 %.

Construction and Implementation of the Off-Grid Zero Emissions Building

2010 ◽  
Author(s):  
Justin Kramer ◽  
Brenton Greska ◽  
Anjaneyulu Krothapalli
Keyword(s):  
Natural Gas ◽  
Alternative Energy ◽  
High Efficiency ◽  
Water Electrolysis ◽  
Energy System ◽  
Proton Exchange ◽  
Hot Water ◽  
Environment Design ◽  
Energy And Environment ◽  
Office Space

This paper deals with the construction and implementation of the Off-Grid Zero Emissions Building (OGZEB), a project undertaken by the Energy Sustainability Center (ESC), formally the Sustainable Energy Science and Engineering Center (SESEC), at the Florida State University (FSU). The project involves the design, construction and operation of a completely solar-powered building that achieves LEED-NC (Leadership in Energy and Environment Design-New Construction) platinum certification. The 1064 square foot building is partitioned such that 800 square feet is a two bedroom, graduate student style flat with the remaining 264 square feet serving as office space. This arrangement allows the building to serve as an energy efficient model for campus designers in student living and office space. The building also serves as a prototype for developing and implementing cutting edge, alternative energy technologies in both residential and commercial settings. For example, hydrogen is used extensively in meeting the energy needs of the OGZEB. In lieu of high efficiency batteries, the excess electricity produced by the buildings photovoltaic (PV) panels is used to generate hydrogen via water electrolysis for long term energy storage. The hydrogen is stored on-site until needed for either generating electricity in a Proton Exchange Membrane (PEM) fuel cell stack or combusted in natural gas appliances that have been modified for hydrogen use. The use of hydrogen in modified natural gas appliances, such as an on-demand hot water heater and cook top, is unique to the OGZEB. This paper discusses the problems and solutions that arose during construction and includes detailed schematics of the OGZEBs energy system.

Nanotubular Transition Metal Oxide for Hydrogen Production

2011 ◽  
Vol 364 ◽  
pp. 494-499 ◽  
Author(s):  
Srimala Sreekantan ◽  
E Pei San ◽  
Chin Wei Lai ◽  
Warapong Kregvirat
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Rf Sputtering ◽  
Transition Metal Oxide ◽  
Average Diameter ◽  
Ammonium Fluoride ◽  
Photocurrent Density ◽  
Electron Hole ◽  
Entire Study ◽  
Metal Oxide Nanotubes

TiO2, transition metal oxide nanotubes were successfully grown by anodizing of titanium foil (Ti) in ethylene glycol electrolyte containing 5wt % hydrogen peroxide and 5wt % ammonium fluoride for 60 minutes at 60V. It was found such electrochemical condition resulted in the formation of nanotube with average diameter of 90nm and length of 6.6 µm. These samples were used to study the effect of W loading by RF sputtering on TiO2 nanotubes. Amorphous TiO2 nanotube substrate leads to enhance incorporation of W instead of anatase. Therefore for the entire study, W was sputtered on amorphous TiO2 nanotube substrate. TiO2 nanotube sputtered below 1 minute resulted in the formation of W-O-Ti while beyond this point; it accumulates to form a self-independent structure of WO3 on the surface of the nanotubes. TiO2 nanotube sputtered for 1minute at 100W and annealed at 450°C exhibited best photocurrent density (1.4 mA/cm2) with photoconversion efficiency of 2.5%. The reason for such behavior is attributed to W6+ ions allows for electron traps that suppress electron-hole recombination and exploit the lower band gap of material to produce a water splitting process by increasing the charge separation and extending the energy range of photoexcitation for the system.

A colloidal heterostructured quantum dot sensitized carbon nanotube–TiO2 hybrid photoanode for high efficiency hydrogen generation

2019 ◽  
Vol 4 (2) ◽  
pp. 404-414 ◽  
Author(s):  
Gurpreet Singh Selopal ◽  
Mahyar Mohammadnezhad ◽  
Fabiola Navarro-Pardo ◽  
François Vidal ◽  
Haiguang Zhao ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Quantum Dot ◽  
High Efficiency ◽  
Hydrogen Generation ◽  
Photocurrent Density ◽  
Control Device

A photoelectrochemical device based on a TiO2/QD–MWCNT (0.015 wt%) hybrid photoanode yields 40% higher photocurrent density than the control device.

CoP@NRGO composite as a high-efficiency water electrolysis catalyst for hydrogen generation

2020 ◽  
Vol 290 ◽  
pp. 121596
Author(s):  
Hongzhi Wang ◽  
Qi Gao ◽  
Shaofeng Sun ◽  
Weiguo Zhang ◽  
Suwei Yao
Keyword(s):  
High Efficiency ◽  
Hydrogen Generation ◽  
Water Electrolysis

High efficiency, Pt-free photoelectrochemical cells for solar hydrogen generation based on “giant” quantum dots

Nano Energy ◽  
2016 ◽  
Vol 27 ◽  
pp. 265-274 ◽  
Author(s):  
Rajesh Adhikari ◽  
Lei Jin ◽  
Fabiola Navarro-Pardo ◽  
Daniele Benetti ◽  
Bandar AlOtaibi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Efficiency ◽  
Hydrogen Generation ◽  
Photoelectrochemical Cells ◽  
Solar Hydrogen

Three-Dimensional Numerical Analysis of Solid Oxide Electrolysis Cells Steam Electrolysis Operation for Hydrogen Production

2015 ◽  
Vol 12 (5) ◽  
Author(s):  
Juhyun Kang ◽  
Joonguen Park ◽  
Joongmyeon Bae
Keyword(s):  
Hydrogen Generation ◽  
Water Electrolysis ◽  
Electrical Energy ◽  
High Energy ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Electrolysis Cells ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cells ◽  
The Relationship

Hydrogen is a resource that provides energy and forms water only after reacting with oxygen. Among the many hydrogen generation systems, solid oxide electrolysis cells (SOECs) have attracted considerable attention as advanced water electrolysis systems because of their high energy conversion efficiency and low use of electrical energy. To find the relationship between operating conditions and the performance of SOECs, research has been conducted both experimentally, using actual SOECs, and numerically, using computational fluid dynamics (CFD). In this investigation, we developed a 3D simulation model to analyze the relationship between the operating conditions and the overall behavior of SOECs due to different contributions to the overpotential. Simulations were performed with various inlet gas compositions of cathode and anode, cathode thickness, and electrode porosity to identify the main parameters related to performance.

Structural, Morphological and Photoelectrochemical Behavior of Hematite Modified by 120 MeV Ag9+ Ions

2009 ◽  
Vol 1217 ◽  
Author(s):  
Aadesh P. Singh ◽  
Saroj Kumari ◽  
Rohit Shrivastav ◽  
Sahab Dass ◽  
Vibha R. Satsangi
Keyword(s):  
Ion Irradiation ◽  
Low Cost ◽  
Photocurrent Density ◽  
Heavy Ion ◽  
High Energy ◽  
Solar Hydrogen ◽  
Raman Analysis ◽  
Solar Hydrogen Production ◽  
Redox Level ◽  
Magnetite Phase

AbstractNanostructured hematite thin film for photoelectrochemical (PEC) splitting of water has great potential in the design of low-cost, environmental friendly solar-hydrogen production. Presently, solar-to-hydrogen conversion efficiency of PEC cell using iron oxide is limited by its poor charge transport due to high recombination losses and mismatch of band edges position with the redox level of water. High energy heavy ion irradiation provides the researchers a new dimension to introduce the desired changes in the behaviour of the material, which largely influence their properties. In order to get efficient PEC system, spray-pyrolytically deposited nanostructured hematite thin films were modified by irradiating the samples with 120 MeV Ag9+ ions with fluences ranging from 5×1011 to 1×1013 ions/cm2. Irradiated samples exhibited a partial transition from the hematite to the magnetite phase and reduction in particle size as indicated by XRD and Raman analysis. SEM picture showed a decrease the thickness and porosity of the films after irradiation. These irradiated films, when used in PEC cell showed significantly higher photocurrent density than unirradiated α-Fe2O3.

scholarly journals Nanostructures of 2d Transition Metal Dichalcogenides for Hydrogen Generation under Alkaline Conditions: From Theoretical Models to Practical Electrocatalysts

2021 ◽  
pp. 25-36
Author(s):  
Zhexu Xi
Keyword(s):  
Transition Metal ◽  
Fossil Fuels ◽  
High Efficiency ◽  
Hydrogen Generation ◽  
Transition Metal Dichalcogenides ◽  
Water Electrolysis ◽  
Theoretical Models ◽  
Slow Kinetics ◽  
Alkaline Conditions ◽  
Metal Dichalcogenides

Hydrogen has been considered as the cleanest renewable energy and the ideal alternative to fossil fuels. Electrocatalytic Hydrogen Evolution Reaction (HER) via water splitting also plays an indispensable role in high-efficiency energy con- version. Compared with the well-investigated acidic HER, the relatively slow kinetics and unclear mechanism of HER in alkaline environments largely make the design of electrocatalysts a trial-and-error process, retarding the scalable development of efficient, sustainable hydrogen production. Furthermore, two-dimensional transition metal dichalcogenides (2D TMDs) have been demonstrated to be promising acidic/ alkaline HER catalysts in water electrolysis due to their outstanding atom-level thickness and surface-based properties.

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