A STUDY OF THE C-NO REACTION BY USING ISOTOPICALLY LABELED C AND NO

The role of O- and N-containing surface species in the course of NO re duction over phenol-formaldehyde resin char and amorphous C-13 was inv estigated. The presence of O-containing complexes on the char surface was shown to increase the reactivity towards NO by providing free reac tive sites. The presence of O-2 also enhanced the NO reduction reactio n greatly. A mass balance during temperature-programmed reaction indic ated nitrogen accumulation on the char surface. The reaction mechanism was examined by a transient kinetic approach, in which the reactant g as was switched from (NO)-N-14-O-16 to (NO)-N-15-O-18. The surface N-c ontaining species produced and accumulated in the first stage, C(N-14) , was found to react with (NO)-N-15-O-18, yielding (NN)-N-14-N-15. Thi s indicated that one N-2 formation path is the reaction between nitrog en-containing surface compound and NO. (C) 1997 Elsevier Science Ltd.