Hi all,
I have prepared some biomass-based activated carbon samples which are powdered in nature. To analyze for XPS, I had prepared the slides by dispersing the sample in ethanol and drop cast on to Si wafer. However, once it dried, the sample was coming out of the surface and unable to process further to complete the analysis. Can anybody suggest a suitable method to prepare the slides for XPS, especially for these kinds of powdered activated carbon samples?
Thanks in advance.
ANSARI P
Dear Ansari Palliyarayil,
For powder samples you can use carbon or copper double-sided conductive tape, you directly put the powder on the tape and take care that there are no gaps. You could also make wafers with a hydraulic press and use the tape to fix the samples on the sample holder.
Best,
Jhonatan
Ansari Palliyarayil
You may use the pellet of your powdered sample. If pellet of the material is not stable then you may use silver paste on sample holder and stick the powder on paste.
Generally, we use Indium metal foil and burnish the powder into the foil.Burnish is a fancy way of saying we use a 1/4 diameter quartz rod with a smooth round end to work the sample into the Indium surface. This type of prep generally reduces the effect of charging and they will not "blow away' as they are put into vacuum. Since your samples are supported on carbon, you probably wont have charging problems, but be aware that they can lead to large peak shifts.
All the above suggestions will work well. Nevertheless, due to simplicity, it would be easier to put it on cupper tape (double sided) or carbon tape - and press it a bit without contamining.
I had no issue measuring powder samples (e.g. TiO2 nanoparticles, nanosheets, etc.), as long as the layer you put on the tape is not too thick. And be sure to check if you have peak shifts and need than to adjust the measuring range.
As you have activated carbon sample, maybe Cu tape would be easier (to exclude from begining the case of some influence in C peak from C tape, if your layer has some gaps - though for me this does not usually occur).
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