The parallel dehydrative and dehydrogenative catalytic action of γ-Al2O3 pure and doped by MgO: Kinetics, selectivity, time dependence of catalytic behaviour, mechanisms and interpretations

Patermarakis, G

dc.contributor.author	Patermarakis, G	en
dc.date.accessioned	2014-03-01T01:19:37Z
dc.date.available	2014-03-01T01:19:37Z
dc.date.issued	2003	en
dc.identifier.issn	0926860X	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/15615
dc.subject	γ-Al2O3 + (0 and 1% MgO)	en
dc.subject	Dehydration	en
dc.subject	Dehydrogenation	en
dc.subject	Formic acid decomposition	en
dc.subject	Mechanisms	en
dc.subject	Reactions kinetics	en
dc.subject	Selectivity	en
dc.subject	Temperature dependence of ageing and activation	en
dc.subject.other	Activation energy	en
dc.subject.other	Catalysis	en
dc.subject.other	Doping (additives)	en
dc.subject.other	Magnesia	en
dc.subject.other	Positive ions	en
dc.subject.other	Reaction kinetics	en
dc.subject.other	Dehydrogentaion	en
dc.subject.other	Alumina	en
dc.title	The parallel dehydrative and dehydrogenative catalytic action of γ-Al2O3 pure and doped by MgO: Kinetics, selectivity, time dependence of catalytic behaviour, mechanisms and interpretations	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0926-860X(03)00411-3	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0926-860X(03)00411-3	en
heal.publicationDate	2003	en
heal.abstract	The catalytic test reaction of HCOOH decomposition on pure γ-Al 2O3 and doped (+ MgO (1% w/w)) was studied at temperatures 275-400°C. A double dehydrative and dehydrogenative, instead the thought single dehydrative, behaviour of γ-Al2O 3 was disclosed. The dehydration activity is higher for pure alumina and decreases with operation time while the dehydrogenation activity is higher for doped and increases with time at the higher but decreases at the lower temperatures showing an unusual temperature dependent activation and ageing. Doping and increase of temperature reduce dehydration selectivity. It decreases with operation time at higher but increases at lower temperatures. The Arrhenius kinetic parameters of reactions differ strongly. Activation energy of dehydration seems unaffected and pre-exponential factor slightly affected by catalyst kind and operation time. Parameters concerning dehydrogenation are affected slightly by catalyst kind and strongly by operation time. Based on an atomic scale structure analysis and results, two dehydration and one dehydrogenation coexisting mechanisms stemming from identical initial step of dissociative adsorption of HCOOH as H+ and HCOO- were suggested interpreting the results. The observed behaviour is due to changes of surface atomic spacing by doping Mg2+ and of mean distances of adsorptive pair sites with operation time caused by the second mechanism. © 2003 Elsevier B.V. All rights reserved.	en
heal.journalName	Applied Catalysis A: General	en
dc.identifier.doi	10.1016/S0926-860X(03)00411-3	en
dc.identifier.volume	252	en
dc.identifier.issue	2	en
dc.identifier.spage	231	en
dc.identifier.epage	241	en