Surface reactivity of hydroxyl radicals formed upon catalytic decomposition of H2O2 on ZrO2
2015 (English)In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, Vol. 400, 49-55 p.Article in journal (Refereed) Published
In this work, the surface reactivity of hydroxyl radicals formed upon catalytic decomposition of H2O2 on ZrO2 in the presence of Tris(hydroxymethyl) aminomethane was studied experimentally. Two sets of competition experiments were performed: the competition between H2O2 and Tris for the surface bound hydroxyl radical (HO) and between O2 and H2O2 for the hydroxymethyl radical (CH2OH) (precursor for formaldehyde). A 5-fold increase in initial concentration of Tris or H2O2 does not lead to a 5-fold increase in CH2O formation (only by a factor of 2-3 in the studied concentration range). The O2-dependent enhancement of the final production of CH2O becomes weaker upon increasing the initial concentration of H2O2 from 0.5 mM to 5 mM. The final production of CH2O becomes independent of the concentration of Tris when [Tris]0 is above 100 mM, i.e., the surface is saturated with Tris at this concentration. Based on the experimental results, a site-specific mechanism of H2O2 decomposition on the surface of ZrO2 was proposed. This model was used for numerical simulations of the dynamics of the reaction system. The kinetics was simulated using the kinetic simulation software Gepasi 3.0 and the results are in good agreement with the experimental observations.
Place, publisher, year, edition, pages
2015. Vol. 400, 49-55 p.
Catalysis, Hydrogen peroxide, Hydroxyl radical, Oxide, Surface, Computer software, Methanol, Oxides, Surfaces, Catalytic decomposition, Concentration ranges, Hydroxyl radicals, Initial concentration, Kinetic simulation, Reaction system, Surface reactivity, Trishydroxymethylaminomethane, Zirconium alloys
IdentifiersURN: urn:nbn:se:kth:diva-167732DOI: 10.1016/j.molcata.2015.02.002ISI: 000353248000007ScopusID: 2-s2.0-84922771691OAI: oai:DiVA.org:kth-167732DiVA: diva2:815666
QC 201506012015-06-012015-05-222015-08-26Bibliographically approved