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First Genesis Spacecraft Samples Shipped to Researchers
Scientists at NASA's Johnson Space Center in Houston have shipped pieces of the Genesis polished aluminium collector to researchers at Washington University in St. Louis, marking the first distribution of a Genesis scientific sample from JSC since the science canister arrived there Oct. 4, 2004. The sample, the first to be allocated for Genesis early science analysis, may hold important evidence about the overall composition of the sun.
While much of the solar wind is hydrogen, it is hoped that Genesis captured samples of many elements in the periodic table. An analysis of these elements will help to determine the sun's composition in detail. Several important Genesis science objectives will be investigated as part of the Early Science Return, including studies of noble gas isotopes in bulk solar wind and nitrogen isotopes.
Periodic Table Wordle
16 January, 2009 - 22:08 | by WebElements
Popularity Wordle
This picture is a wordle. This shows the chemical elements in proportion to pages viewed for each on the WebElements periodic table web site. Hydrogen is the most viewed element. The question is, I suppose, is whether any useful information is conveyed? You can see this wordle and others at wordle.net
Might future fuel cells be nickel based?
There seems to be a possibility that nickel compounds might help in the electrolysis of water, the reaction at the centre of hydrogen fuel cells. Researchers at the Joseph Fourier University in Grenoble, and at the French Atomic Energy Commission in Gif-sur-Yvette and attached a nickel compound that mimics hydrogenase enzymes (catalysts) and attached it to the surface of carbon nanotubes. This maximises the catalyst's surface area. The resulting material was tested using a proton-exchange membrane and produced hydrogen from a sulphuric acid solution. The result is only 1% as efficient than commercial platinum catalysts but is stable under typical fuel cell conditions, justifying further study.1
- 1. From Hydrogenases to Noble Metal-Free Catalytic Nanomaterials for H2 Production and Uptake,
, Science, 12/2009, Volume 326, Issue 5958, p.1384 - 1387, (2009)
From Hydrogenases to Noble Metal-Free Catalytic Nanomaterials for H2 Production and Uptake
Abstract: Interconversion of water and hydrogen in unitized regenerative fuel cells is a promising energy storage framework for smoothing out the temporal fluctuations of solar and wind power. However, replacement of presently available platinum catalysts by lower-cost and more abundant materials is a requisite for this technology to become economically viable. Here, we show that the covalent attachment of a nickel bisdiphosphine–based mimic of the active site of hydrogenase enzymes onto multiwalled carbon nanotubes results in a high–surface area cathode material with high catalytic activity under the strongly acidic conditions required in proton exchange membrane technology. Hydrogen evolves from aqueous sulfuric acid solution with very low overvoltages (20 millivolts), and the catalyst exhibits exceptional stability (more than 100,000 turnovers). The same catalyst is also very efficient for hydrogen oxidation in this environment, exhibiting current densities similar to those observed for hydrogenase-based materials.
From Hydrogenases to Noble Metal-Free Catalytic Nanomaterials for H2 Production and Uptake, , Science, 12/2009, Volume 326, Issue 5958, p.1384 - 1387, (2009)A room-temperature titania-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination
Abstract: described is a room-temperature hydrogen sensor comprised of a TiO2-nanotube array able to recover substantially from sensor poisoning through ultraviolet (UV) photocatalytic oxidation of the contaminating agent; in this case, various grades of motor oil. The TiO2 nanotubes comprising the sensor are a mixture of both anatase and rutile phases, having nominal dimensions of 22-nm inner diameter, 13.5-nm wall thickness, and 400-nm length, coated with a 10-nm-thick noncontinuous palladium layer. At 24°C, in response to 1000 ppm of hydrogen, the sensors show a fully reversible change in electrical resistance of approximately 175,000%. Cyclic voltammograms using a 1 N KOH electrolyte under 170 mW/cm2 UV illumination show, for both a clean and an oil-contaminated sensor, anodic current densities of approximately 28 mA/cm2 at 2.5 V. The open circuit oxidation potential shows a shift from 0.5 V to –0.97 V upon UV illumination.
A room-temperature titania-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination, , Journal of Materials Research, 02/2004, Volume 19, Issue 2, p.628?634, (2004)Self-cleaning titania nanotube hydrogen sensors
The Science Blog reports that researchers at Penn State in the USA are developing self-cleaning titania nanotube hydrogen sensors. The hydrogen sensors are titania nanotubes coated with a discontinuous layer of palladium. Hydrogen sensors are widely used in the chemical, petroleum and semiconductor industries. They are also used as diagnostic tools to monitor certain types of bacterial infections.
"The photocatalytic properties of titania nanotubes are so large - a factor of 100 times greater than any other form of titania - that sensor contaminants are efficiently removed with exposure to ultraviolet light, so that the sensors effectively recover or retain their original hydrogen sensitivity in real world application"
"By doping the titania nanotubes with trace amounts of different metals such as tin, gold, silver, copper, niobium and others, a wide variety of chemical sensors can be made. This doping does not alter the photocatalytic properties of the titania nanotubes" says Dr. Craig A. Grimes, associate professor of Electrical Engineering and Materials Science and Engineering.1
- 1. A room-temperature titania-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination,
, Journal of Materials Research, 02/2004, Volume 19, Issue 2, p.628?634, (2004)
Popularity Wordle
This picture is a wordle. This shows the chemical elements in proportion to pages viewed for each on the WebElements periodic table web site. Hydrogen is the most viewed element. The question is, I suppose, is whether any useful information is conveyed? You can see this wordle and others here: Wordle: Chemical elements popularity The Group 1 elements
The Group 1 elements other than hydrogen are called the alkali metals. The Group 1 elements are:
The Group 1 metals are all highly reactive silvery metals that are so reactive to air and moisture that they must be stored under an inert atmosphere or oil. They are all soft and can be cut easily with a knife.
Hydrogen is usually placed at the top of the Group but is not a Group 1 metal.
The electronic configuration of the elements all consist of a lone s-electron outside an inner core of electron corresponding to the previous inert gas.
List of elements by atomic number
| Element name | Element symbol | Atomic number |
|---|---|---|
| Hydrogen | H | 1 |
| Helium | He | 2 |
| Lithium | Li | 3 |
