Hydrogen adsorption, sintered nickel films

Almost every year from 1940 to 1949, Beeck attended the Gordon Research Conference on Catalysis, sometimes accompanied by Wheeler. There he usually presented a report of their recent progress, so the catalysis community was apprised of new developments. A paper on the adsorption of hydrogen on sintered nickel films was published in 1948 (] ). It revealed that the usual very rapid adsorption was accompanied by a slower, activated process. This slower step was attributed to the penetration of hydrogen into regions that had been closed off by thin barriers formed by sintering. The finding resolved, at least in part, the difference between the results obtained initially with evaporated films and those reported for supported nickel catalysts formed by conventional chemical means. 

Before leaving the nickel experiments, it may be well to refer to the experiments on hydrogen adsorption variously reported in the literature. As an example, the work of Maxted and Hassid (13) had as its main objective the measurement of the slow activated adsorption of hydrogen on reduced nickel oxide catalysts. It has been proved by the foregoing that the slow adsorption is actually absorption. When plotting their data as isobars, as was done in Fig. 9, the similarity between these isobars and those obtained with sintered nickel films is evident. 

Figure 5 shows data for catalytic activity, CO adsorption at 23°, surface area by the B.E.T. method using krypton at —196°, and the fast hydrogen adsorption at —196° plotted against the temperature at which the various films were sintered. All quantities were taken as unity for films sintered at 23°C. These experiments clearly indicate that the previously observed slow adsorption of hydrogen on nickel catalysts is not adsorption but is sorption consisting of adsorption and... 

Quite a number of years ago we carried out some experiments on films evaporated from Alloy 99 wire. We observed that films evaporated from this wire exhibited quite different properties than those evaporated from Nickel A or Hoskins 651. The films prepared from Alloy 99 showed (211) preferential orientation and were highly resistant to sintering as measured by the hydrogen adsorption. The activity of these films for carbon monoxide oxidation was 15 times greater than the activity of films prepared from the other nickel wires. For the disproportionation of carbon monoxide, 50-60% more CO2 was found than was theoretically possible. When the wire was heated in hydrogen a large decrease in hydrogen pressure with subsequent water formation was observed. 

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