I would also use acid doped PBI membrane assembly and as acid phosphoric-acid.

Dear Karim Ghaib, did you use any catalyst binder?

No, we used no binder, you need a GDL-material that can fixes the catalyst

We use PTFE for normal PEM, PBI more expensive, Nafion can't stand for high temp.

My suggestion you can use PTFE binder on GDL (carbon paper) and coating

with PBI as end layer. If you do CCM PBI binder maybe better. 

Thanks a lot, Dr. T. Husaini

Thanks Hasan, Hope you will get information.

Regards

Hu