The metal oxide catalysts can be reduced by using H2 gas.  Which depends on reduction temperature of metal. Suppose you are taking pd based catalyst it is reduced at 300 oC for 2h.

What you should take care of is what happens AFTER reduction! In some cases, if a metal is exposed to air (or oxygen) its sudden oxidation can produce an explosion. Be sure to passivate the surface of your catalyst with O2 or air after the reduction step.

From my experience 5% H2 in Inert is sufficient for TPR or insitu reduction. You can use a ramp of 5 to 10 degrees per minute for both types of experiment and a hold time at final temperature of 30 min to 120 min. For catalytic purposes do the reduction in the same apparatus used for the catalytic experiments because of the possibility of leakage during the transfer procedure. In lab scale even reduction in pure H2 is quite safe - in 30 years no problems at all.

Thank you all for the responses and advice. I really do appreciate it.

Still does any of you have any recommended book that details this sort of catalyst practical stuff?

@Thomas Hahn - I am interested to know what kind of apparatus you were using. I kind of stuck on designing apparatus so that my catalysts will not be exposed to air at all. Was your reduction step done in Parr reactor?  which means its not H2 flowing, it would be much easier if I can just do it in a closed system. Then I can open my par reactor in a glove box to add solid and solvent. Is that how you did it? (However, I saw most literature used H2 continuous flow.)

Thank you.

We use an older Micromeritics for TPR and selfmade quartz reactors for insitu reduction for some high temperature reaction catalysts - these are all flow reactors with approx. plug-flow characteristics.

If you use a Parr-Equipment: is your cat in contact to a gas phase (for example H2) or suspended in a liquid in contact with gas phase?

@Neus Blanch Raga - Thank you, that's what I plan to do too (moving everything to the glove box) because the solid is a fine powder and it sticks on the wall. The only way is to open up the reactor and add it.

@Thomas Hanh - Yes my catalyst would be contact to gas phase (no liquid). Basically what I have in mind is that I will reduce cat. in Parr reactor. Once done, then move to glove box, open it, and add solid and solvent. My concern is that the reduction step is not done in open system. Do you have any knowledge of that? Thank you.

I understand - from the known amount of catalyst(precursor) you fill in, you can calculate the amount of H2 necessary for full reduction theoretically. I would expect for 2- to 3-fold excess H2 no further problems. Perhaps it is possible from H2-pressure before and after the reduction experiment to get an impression reduction was done or not. I have no experience with this type of reactors!

A further disadvantage of the procedure without use of classical TPR may be, you have no exact information about the real degree of reduction of your catalyst.

Dear Phongpreecha,

thanks for the interesting question, I agree with our colleagues that you need to do first TPR, to see at what temperature your catalyst is reduced and 5%H2/Ar is a good gas feed to reduce the catalyst. 

However, You need to consider first the preparation method of your support, which affect the final  prepared catalyst. Alumina can be used as an active catalyst as it showed acidic sites (mainly Lewis acidic sites) and also it can be used as a support and this is due to its high surface area, mechanically stable  and the porous structure.

 For instance, different precursor and calcination temperatures can lead to different types of alumina support in term of acidity, surface area, activity....etc. Please find the attached paper that discussed the different phases of alumina and the effect of the precursor, calcination temperature on the prepared alumina catalyst 

Have a good day

Ahmed

Please check out this recent publication at Nature journal about the preparation of highly active alumina catalyst from foil waste

http://rdcu.be/ttIz

All the best 

Ahmed