Photoactivated and photopassivated benzylic oxidation catalyzed by pristine and oxidized carbons

The link between the structure of carbons and their performance toward catalytic benzylic oxidation by air is studied. Catalytic activity and selectivity of pristine and oxidized carbons can be enhanced, altered, or suppressed by ambient light. The photocatalytical performance of a carbonaceous material depends on the presence of defects, surface area, porosity, and surface oxidation. Adsorption of the hydroperoxide intermediate on the catalyst's surface is suggested as a key process that links the structure of the carbonaceous material with its catalytic activity. The potential of catalysis by carbon black and photocatalysis by graphite nanofibers for greener organic synthesis has been demonstrated.

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► Catalytic activity of carbons toward oxidation of p-xylene by air and the distribution of the reaction products depend on their structure and oxidation, and can be either increased or suppressed by ambient light.
► High surface area and large pores may lead to unexpected significant photopassivation of the catalyst.
► The potential of catalysis by carbon black and photocatalysis by graphite nanofibers for greener organic synthesis has been demonstrated.