Photoinduced reactions occurring on activated carbons. A combined photooxidation and ESR study

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Abstract

This work demonstrates the ability of ash-free activated carbons to interact with UV light to promote the photooxidation of phenol in solution through the formation of radical species. Our results show that in the absence of inorganic impurities or semiconductor additives, the photodegradation efficiency of the studied activated carbons has to be ascribed to the carbon matrix itself. Hydroxyl radicals have been detected by spin trapping electron spin resonance spectroscopy upon IN irradiation of the activated carbon suspensions in aqueous solution. Although the ability to photogenerate radicals upon irradiation is well known in inorganic semiconductors (such as titanium dioxide) or carbon/semiconductor composites, we herein demonstrate the capacity of the carbon matrix alone to interact with UV light, generating reactive species that would be responsible for the observed photoinduced reaction using carbons alone in the absence of semiconductor additives. Thus, the conventional interpretation of the enhanced photodegradation efficiency of carbon/semiconductor photocatalysts -so far attributed to synergistic and confinement effects, and minimized surface recombination of the charge carriers- should be reconsidered to account for the radicals photogenerated when the carbons are exposed to UV light. (c) 2012 Elsevier B.V. All rights reserved.
Original languageUnknown
Pages (from-to)1-8
JournalApplied Catalysis A-General
Volume452
Issue numberNA
DOIs
Publication statusPublished - 1 Jan 2013

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