Brunauer, Emmett, Teller , hydrogen

In addition to actual synthesis tests, fresh and used catalysts were investigated extensively in order to determine the effect of steam on catalyst activity and catalyst stability. This was done by measurement of surface areas. Whereas the Brunauer-Emmett-Teller (BET) area (4) is a measure of the total surface area, the volume of chemisorbed hydrogen is a measure only of the exposed metallic nickel area and therefore should be a truer measure of the catalytically active area. The H2 chemisorption measurement data are summarized in Table III. For fresh reduced catalyst, activity was equivalent to 11.2 ml/g. When this reduced catalyst was treated with a mixture of hydrogen and steam, it lost 27% of its activity. This activity loss is definitely caused by steam since a... 

Determination of surface areas by Brunauer-Emmett-Teller (BET) isotherms is also an important method for the characterization of amorphous catalysts. For example, the effects of different pretreatments have been followed by measuring BET surface areas (37, 38, 43). BET measurements revealed a dramatic increase in surface areas concomitant with a substantial increase in catalytic activities for Zr-containing amorphous alloys (48, 53-56) during the early period of hydrogenation of CO. 

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