Interaction of oxygen and hydrogen with platinum in pulse gas chromatography
1978; Elsevier BV; Volume: 152; Issue: 2 Linguagem: Inglês
10.1016/s0021-9673(00)85073-6
ISSN1873-3778
AutoresT. Paryjczak, W. K. Jóźwiak, J. Góralski,
Tópico(s)Advanced Chemical Sensor Technologies
ResumoThe interaction of oxygen and hydrogen with the surfaces of platinum black, platinum-silica and platinum-alumina catalysts within the temperature range 196–970°K was examined by pulse gas chromatography. Chemisorption of oxygen and hydrogen was carried out on a “clean” platinum surface and titrations of the oxidized surface with hydrogen were performed together with those of the reverse reaction, i.e., titration of the reduced surface with oxygen. We were able to define the extent of slow, reversible hydrogen sorption within a wide temperature range, desorption of oxygen from the platinum surface and the formation of an oxide multilayer at higher temperatures. The results indicate that the stoichiometries of the surface interactions between platinum and oxygen and between platinum and irreversibly chemisorbed hydrogen are the same and approximate to unity: O/Pt2 ≈ H/Pt5 ≈ 1. The temperature range 300–570°K is suitable for determining platinum dispersions by means of oxygen and hydrogen chemisorption.
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