Abstract:I n h a l t s u b e r s i c h t . Bei tribomechanischer Beanspruchung von Gold in C0,-Atmosphare konnte iiber die radioaktive Markierung beider Phasender unmittelbare Kachweis fiir eine Umsetzung zu Kohlenstoff und Goldoxid erbracht werden. Das Goldoxid wurde im IR-Spektrum als Au,O, identifiziert. Durch diese Reaktion wird an Hand der freien Reaktionsarbeit mit einem Betrag von 90 kcal/Grammatom ein Beispiel fur die durch den Bearbeitungsprozell gelieferten hohen Energiebetrage gegeben. Diese Reaktionsarbeit … Show more
“…The last fact obviously explains the substantial decrease of the activation energy for the hydrogenation of carbon dioxide to methane at the mechanically activated catalyst Ru-MgO observed, for example, in [70]. We note also that the increase in the free energy of the solid reagents as a result of the accumulation of mechanical energy in them makes it possible to conduct thermodynamically forbidden processes, such as the oxidation of gold to Au 2 O 3 by carbon dioxide, under the conditions of mechanical activation [130]. For such a reaction the change of free energy DG at 571 K amounts to +377 kJ/mol, and it definitely could not be realized by thermal means.…”
Section: The Nature Of the Active Centers Generated By Mechanical Actmentioning
Heterogeneous-catalytic reactions on solid-phase catalysts activated by mechanical treatment are discussed. Attention is mainly focused on investigations into the nature of the active centers of the catalystsnonequilibrium states -formed by mechanical activation of the solids.
“…The last fact obviously explains the substantial decrease of the activation energy for the hydrogenation of carbon dioxide to methane at the mechanically activated catalyst Ru-MgO observed, for example, in [70]. We note also that the increase in the free energy of the solid reagents as a result of the accumulation of mechanical energy in them makes it possible to conduct thermodynamically forbidden processes, such as the oxidation of gold to Au 2 O 3 by carbon dioxide, under the conditions of mechanical activation [130]. For such a reaction the change of free energy DG at 571 K amounts to +377 kJ/mol, and it definitely could not be realized by thermal means.…”
Section: The Nature Of the Active Centers Generated By Mechanical Actmentioning
Heterogeneous-catalytic reactions on solid-phase catalysts activated by mechanical treatment are discussed. Attention is mainly focused on investigations into the nature of the active centers of the catalystsnonequilibrium states -formed by mechanical activation of the solids.
“…The reactivity of solids may often be considerably enhanced by mechanical treatment. Even such reactions as the formation of Au 2 0 3 and C from Au and C0 2 , the formation of CuO or Cu 2 0 and C from Cu and C0 2 , which cannot be accomplished thermally as a result of extremely negative affinity, proceed under mechanical treatment with a measurable velocity 28 l.…”
“…A legtöbb esetben a reakciók értelmezhetők alapvető termodinamikai összefüggésekkel is, a Természetesen akadnak olyan reakciók is melyek egyensúlyi termodinamikával nem írhatók le, ilyen például az arany oxidációja szén-dioxiddal [57]. Ezekben az esetekben érdemes irreverzibilis termodinamikát használni a folyamatok értelmezésére [58].…”
Section: A Mechanokémiai Reakciók Termodinamikájaunclassified
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