Artificial Photosynthesis - Use of a Ferroelectric Photocatalyst

2012 ◽  
Vol 1446 ◽  
Author(s):  
Steve Dunn ◽  
Matt Stock
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Titanium Dioxide ◽  
Lithium Niobate ◽  
Gas Phase ◽  
Remnant Polarization ◽  
Artificial Photosynthesis ◽  
Reaction Pathway ◽  
Mercury Lamp ◽  
Low Levels

ABSTRACTThe solid-gas phase photoassisted reduction of carbon dioxide (artificial photosynthesis) was performed using ferroelectric lithium niobate and titanium dioxide as photocatalysts. Illumination with a high pressure mercury lamp and visible sunlight showed lithium niobate achieved unexpectedly high conversion of CO2 to products despite the low levels of band gap light available and outperformed titanium dioxide under the conditions used. The high reaction efficiency of lithium niobate is explained due to its strong remnant polarization (70 μC/cm2) thought to allow longer lifetime of photo induced carriers as well as an alternative reaction pathway.

scholarly journals Gas-Phase Photocatalytic Oxidation of Dimethylamine: The Reaction Pathway and Kinetics

2007 ◽  
Vol 2007 ◽  
pp. 1-4
Author(s):  
Anna Kachina ◽  
Sergei Preis ◽  
Juha Kallas
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
Continuous Flow ◽  
Kinetic Data ◽  
Photocatalytic Oxidation ◽  
Reaction Pathway ◽  
Tubular Reactor ◽  
Order Process ◽  
First Order ◽  
Long Run

Gas-phase photocatalytic oxidation (PCO) and thermal catalytic oxidation (TCO) of dimethylamine (DMA) on titanium dioxide was studied in a continuous flow simple tubular reactor. Volatile PCO products of DMA included ammonia, formamide, carbon dioxide, and water. Ammonia was further oxidized in minor amounts to nitrous oxide and nitrogen dioxide. Effective at 573 K, TCO resulted in the formation of ammonia, hydrogen cyanide, carbon monoxide, carbon dioxide, and water. The PCO kinetic data fit well to the monomolecular Langmuir-Hinshelwood model, whereas TCO kinetic behaviour matched the first-order process. No deactivation of the photocatalyst during the multiple long-run experiments was observed.

Solubility of carbon dioxide in polyethylene/titanium dioxide composite under high pressure and temperature

2002 ◽  
Vol 86 (2) ◽  
pp. 282-288 ◽  
Author(s):  
Surat Areerat ◽  
Yusuke Hayata ◽  
Ryuichi Katsumoto ◽  
Tadahiro Kegasawa ◽  
Hideo Egami ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Titanium Dioxide ◽  
High Pressure And Temperature

Gas-phase pyrolysis of thiopheneacetic acids, thienylethanols, and related compounds — protophilicity of ring π-electrons and relative acidities of hydrogen-bond donors of hydroxyl groups

2002 ◽  
Vol 80 (5) ◽  
pp. 499-503 ◽  
Author(s):  
Ibtehal A Al-Juwaiser ◽  
Nouria A Al-Awadi ◽  
Osman ME El-Dusouqui
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Bond ◽  
Gas Phase ◽  
Kinetic Data ◽  
Reaction Pathway ◽  
Hydroxyl Groups ◽  
Pyrolysis Kinetics ◽  
Elimination Reactions ◽  
Related Compounds ◽  
Phase Elimination

Based on kinetic data of thermal gas-phase elimination reactions, the following Arrhenius log A (s–1) and Ea (kJ mol–1) values, respectively, are obtained: 10.76 and 153.5 for 3-thiopheneacetic acid (1), 10.08 and 149.4 for 2-thiopheneacetic acid (2), 12.04 and 207.1 for 2-(3-thienyl)ethanol (3), 11.55 and 203.3 for 2-(2-thienyl)ethanol (4), 10.91 and 123.4 for 2-thiopheneglyoxylic acid (5), 11.05 and 223.8 for 1-(2-thienyl)propan-1-one (6), and 10.33 and 149.8 for 3-thiophenemalonic acid (7). The products of these pyrolytic reactions were either carbon dioxide or formaldehyde in addition to methylthiophene or thiophenecarboxaldehyde. Both positional and molecular reactivities of the substrates and related compounds are compared, and the results are rationalized on the basis of a reaction pathway involving a concerted six-membered transition state.Key words: thiophenes, gas-phase, pyrolysis, kinetics, mechanism.

A photoelectron microscope study of surfaces

1989 ◽  
Vol 47 ◽  
pp. 10-11
Author(s):  
W. Engel ◽  
M. Kordesch ◽  
A. M. Bradshaw ◽  
E. Zeitler
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Field Strength ◽  
Uv Light ◽  
Physical Property ◽  
Photon Flux ◽  
Mercury Lamp ◽  
Object Surface ◽  
The Sixties ◽  
Physical Features

Photoelectron microscopy is as old as electron microscopy itself. Electrons liberated from the object surface by photons are utilized to form an image that is a map of the object's emissivity. This physical property is a function of many parameters, some depending on the physical features of the objects and others on the conditions of the instrument rendering the image.The electron-optical situation is tricky, since the lateral resolution increases with the electric field strength at the object's surface. This, in turn, leads to small distances between the electrodes, restricting the photon flux that should be high for the sake of resolution.The electron-optical development came to fruition in the sixties. Figure 1a shows a typical photoelectron image of a polycrystalline tantalum sample irradiated by the UV light of a high-pressure mercury lamp.

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

scholarly journals The degradation of cellulose in ionic mixture solutions under the high pressure of carbon dioxide

RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3484-3494
Author(s):  
Sumarno ◽  
Prida Novarita Trisanti ◽  
Bramantyo Airlangga ◽  
Novi Eka Mayangsari ◽  
Agus Haryono
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Hydrothermal Process ◽  
Reducing Sugar

Cellulose processing by a hydrothermal process as well as in combination with a sonication pretreatment under a CO2 pressurization that affects the morphology and reducing sugar products.

Graph theory-based reaction pathway searches and DFT calculations for the mechanism studies of free radical-initiated peptide sequencing mass spectrometry (FRIPS MS): a model gas-phase reaction of GGR tri-peptide

2020 ◽  
Vol 22 (9) ◽  
pp. 5057-5069 ◽  
Author(s):  
Jae-ung Lee ◽  
Yeonjoon Kim ◽  
Woo Youn Kim ◽  
Han Bin Oh
Keyword(s):  
Graph Theory ◽  
Dft Calculations ◽  
Gas Phase ◽  
Density Functional ◽  
Reaction Pathway ◽  
Peptide Sequencing ◽  
Phase Reaction ◽  
Functional Theory ◽  
Fragmentation Mechanisms ◽  
Gas Phase Fragmentation

A new approach for elucidating gas-phase fragmentation mechanisms is proposed: graph theory-based reaction pathway searches (ACE-Reaction program) and density functional theory (DFT) calculations.

Sign in / Sign up

Export Citation Format

Share Document