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# Laurent Menard <lmenard@uiuc.edu>
# requesting 5 days, at minimum=3 days
# beamline 33BM, EXAFS of oxide supported metal nanoparticles and solution spectroelectrochemistry of Au clusters
# instrument 33BM-B XAFS
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# top:/home/www/beamtime-requests/req01002.txt
# UNICAT Member Beam Time Request  #1002
# created Wed May 24 16:34:32 CDT 2006
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apsrun:
	2006-02

beamline:
	33BM

collaboration:
	Yes

collaborator_Jenia:
	ON

contact:
	lmenard@uiuc.edu

days:
	5

description:
	Self-supported Au on TiO2 samples (1-5 wt %) and Pt/Ir on Al2O3 samples (total metal wt% = 0.5 - 2) will be mounted in an in-situ catalysis cell. The sample will be measured at several different temperatures (liq N2 to 400 deg. C) under a hydrogen atmosphere (3.7% H2, balance He, nonflammable).  The sample will also be measured under He atmosphere.

Stainless steel tubing will be used for flow of all gases. 

Temperature control of the cell will be achieved for high temperatures with a resistive heating element and for low temperatures with a cold finger cooled with liquid nitrogen. Appropriate protective equipment (face shield, gloves) will be used when working with cryogenic fluids.

The sample cell is of stainless steel construction. The beam passes through a Kaptan film window.  Temperature is monitored with a thermocouple.  The flanges of the sample cell are cooled with water flowing through the cell to prevent heating of the cell body.         
       
Gases will be used at 1 atm pressure and flow rates of 70 cc/min.       

Gases will be exhausted through the exhaust fan on the roof of the building.       
      
The heating element is not exposed and there is consequently no danger of accidental contact.  A sign will be posted on the hutch door warning of a heat source and LN2 when the heating or cooling is required during experiment.       
       
If time allows spectroelectrochemical experiments will be performed on a solution of Au nanoparticles.  A solution of gold nanoparticles and electrolyte (tetrabutylammonium perchlorate) in methylene chloride will be added to a spectroelectrochemical cell (schematics attached) in a chemical fume hood.  The interfaces between the electrodes and the cell will be sealed with Teflon tape to prevent evaporation of methylene chloride and then transferred to the beamline and mounted in the hutch for transmission/fluorescence measurements.  The solution will be purged with Ar (1 atm, ~1 sccm).

The potential of the electrochemical cell will be controlled by a CH Instruments electrochemical analyzer between +2 and -2 V (microamp currents) while XAFS spectra are scanned.  The electrochemical analyzer will be located inside the hutch and interfaced to a laptop computer outside of the hutch.

equipment_required:
	

experiment:
	EXAFS of oxide supported metal nanoparticles and solution spectroelectrochemistry of Au clusters

foreign_nationals:
	

hazards:
	

instrument:
	33BM-B XAFS

instrument_other:
	

minimumdays:
	3

name:
	Laurent Menard

nonmembers:
	

submit:
	Submit

unacceptable_dates:
	

z34ID_details:
	


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