XPS OF NITROGEN-CONTAINING FUNCTIONAL-GROUPS FORMED DURING THE C-NO REACTION

The reaction between nitrogen oxides and carbon generates nitrogen-con taining complexes on the carbon surface. The use of X-ray photoelectro n spectroscopy allowed the characterization of these surface complexes . Five distinct structures have been distinguished, corresponding to n itrogen incorporated in five- and six-member ring as well as pyridine N-oxide and nitrate. Temperature has been found to be the determinant in the repartition of surface species. The reaction with NO-O-2 at 600 degrees C has produced both pyrrolic and pyridinic nitrogens, while t he reaction with NO at 950 degrees C mainly produced a pyridinic one. Quaternary nitrogen increased upon the heat treatment in He at 950 deg rees C after the char was reacted with NO-O-2 at 600 degrees C.