Catalytically Active Surface Area Per Unit Weight of Catalyst

2 Catalytically Active Surface Area Per Unit Weight of Catalyst 

Hydrogen adsorption at relatively low temperatures is often specific for metal surfaces. Because of the very low boiling point of hydrogen, physical adsorption is negligible unless the temperature is low, viz. ca 77 K, and the pressure is high, 

Nickel surfaces and surfaces of supported precious metal particles can fairly reliably be calculated from the extent of hydrogen adsorption. The metal surface must first be reduced and the adsorbed hydrogen must subsequently be removed by evacuation at elevated temperatures. It is important that a sufficiently high pumping speed is maintained in the vessel containing the metal catalyst, because complete removal of hydrogen requires a low pressure and a relatively long time. 

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