Platinum nanoparticles fluorescence

In situ redispersion of platinum nanoparticles on ceria-based oxide for vehicle exhaust catalysts

Supported precious metals are used to facilitate many industrial catalytic processes. Platinum (Pt) in particular is used for the cleaning up of vehicle exhaust emissions. When the vehicle exhaust catalyst is exposed to high temperatures (~800°C and above), the highly dispersed metal nanoparticles agglomerate and sinter, decreasing the active surface area, which causes a loss of catalytic activity (i.e. deactivation). Exhaust gases exiting from gasoline engines change quickly during operation. Temperatures can rise transiently to around 1000°C and the exhaust gas composition itself fluctuates quickly between oxidative and reductive compositions. Hence, in situ dynamic observation on the sintering and redispersion phenomena of the precious metal in the automotive catalysts is very important indeed.

Real-time observation of the sintering/redispersion behaviour of Pt was made possible by the fluorescence yield variant (Turbo-XAS) of energy dispersive XAFS developed by Pascarelli et al. at ID24 [1]. An in situ cell optimised for fluorescence detection was designed for this experiment [2]. Fluorescence yield Turbo-XAS data collected at the Pt LIII edge on 2 wt% Pt/Ce-Zr-Y mixed oxide (referred to as CZY) catalysts under in situ conditions are shown in Figure 119. The signal to noise ratio on this data is improved with respect to our previous transmission XAS study on Pt/CZY, which showed that the combination of low levels of Pt in the catalysts, with high levels of heavy, absorbing, elements such as Ce and Zr severely compromises the conventional, transmission based experiments, making quantitative analysis very difficult [3].

Fig. 119: Serial time-resolved Pt LIII edge XANES spectra (6 seconds each) of 2 wt% Pt/CZY catalyst under cyclical oxidising/reducing. Variation in the first hundred spectra under oxidising/reducing atmosphere at around 400ºC.

See also:
Platinum Manipulated With Photosynthetic Technique.: An article from: Nanoparticle News
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Is what we see based on what we believe?

by PositiveOption

Because I believe
1 Corinthians 3:19 For the wisdom of this world is foolishness with God. For it is written, He taketh the wise in their own craftiness.
That means I see that, because the cell's nanotechnology and complexity on multiple levels is unmatched by all the engineers on the earth combined, it is a paradox if it comes from a natural cause
But Science does not they say there two ways to get a efficient design?
1.Designers apply their energy and intelligence to trial and error and create a efficient design like the motor of the space shuttle
2

It is a trust in knowlede and it's source

by PositiveOption

One who loves God will see what they believe and the ones who trust science will believe what they see
1 Corinthians 3:19 For the wisdom of this world is foolishness with God. For it is written, He taketh the wise in their own craftiness.
That means I see that, because the cell's nanotechnology and complexity on multiple levels is unmatched by all the engineers on the earth combined, it is a paradox if it comes from a natural cause
But Science does not see it that way they say there two ways to get a efficient design?

Nanotechnology is not ready . how about

by bionecr

People move some of their interest to something that could be ready sooner. Nanotechnology has been given alot of press, and that may have caused us to over look the possibilities of accupuncture. Or most people are idiots and a small percentage of us do most of the creative thinking Why havent we brought the technique of accupuncture into the 21st century. Hollow micro needles delivering anti biotics to localized areas of the body, or chemotherapy delivered into the closest cappilaries. Such a waste of accupuncturists today. What if this technique were used in areas around the lungs for tuberculosis would we have cleared up infections with less risk of creating drug esistant strains

Nanotubes Increase Solar PV Conductivity 100 Million-Fold  — Sourceable
Carbon-based nanostructures are already being used as materials in solar cells with increasing frequency, yet their ability to enhance electrical performance has thus far been hampered by limited ability to assemble orderly networks using the materials.

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