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Confirming the Formation of Hydroxyl Radicals in the Catalytic Decomposition of H 2 O 2 on Metal Oxides Using Coumarin as a Probe
Author(s) -
Maier Annika Carolin,
Iglebaek Ena Herceglija,
Jonsson Mats
Publication year - 2019
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201901316
Subject(s) - radical , chemistry , hydroxyl radical , hydrogen peroxide , catalysis , aqueous solution , photochemistry , decomposition , oxide , coumarin , metal , inorganic chemistry , organic chemistry
Hydrogen peroxide can be catalytically decomposed to O 2 and H 2 O on metal oxide surfaces in contact with aqueous solutions containing H 2 O 2 . The initial step in this process has been proposed to be the formation of surface‐bound hydroxyl radicals which has recently been verified using tris as a radical scavenger. Here, we make use of the unique fluorescent product 7‐hydroxycoumarin formed in the reaction between hydroxyl radicals and coumarin to probe the formation of surface‐bound hydroxyl radicals. The experiments clearly show that 7‐hydroxycoumarin is formed upon catalytic decomposition of H 2 O 2 in aqueous suspensions containing ZrO 2 ‐particles and coumarin, thereby confirming the formation of surface‐bound hydroxyl radicals in this process. The results are quantitatively compared to results on the same system using tris as a probe for hydroxyl radicals. The effects of the two probes on the system under study are compared and it is concluded that coumarin has a significantly lower impact on the system.