Catalysis by Nitrogen-Containing Carbons

UV-irradiated Ti02, and similarly ZnO and some other oxides, catalyze oxidation with dioxygen. ESR measurements of ZnO irradiated with UV light in the presence of O2 showed the existence of and 0 . The predominant species below 443 K is O, and 0 at higher temperatures [187], The holes, h+, in the valence band of the irradiated oxides can react with 0H ions on the surface, producing OH radicals, which are also very reactive. 

In the dehydrochlorination of alkyl chlorides, dimerization of the alkyl radicals was observed after splitting off of Cl ions (Section 7.5). This is also an indication that electrons from the carbon are involved. 

The catalyzed oxidation of sulfurous acid, oxalic acid, or SO2 is inhibited by chemisorbed oxygen or chlorine, two electronegative elements (see Sections 7.3.1 section 7.3.3). The inhibition correlated well with the amount of chemisorbed chlorine on Anthralur or NH3-treated Anthralur [98], and the deactivation could be reversed by heat treatment under N2 or H2 at 1173 K [96] or with NH3 

In many cases the effect of nitrogen doping of carbons on their catalytic properties might be due to two overlapping effects, catalysis by basic surface sites and by electron donation. 

The dedicated work of many students in my research group, cited in the references with their theses or as co-authors, is gratefully acknowledged. 

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