XPS determination of the forms of nitrogen in coal pyrolysis chars

摘要

The N 1s spectra from four pulverized Australian coals and their chars produced by pyrolysis for 2 s at 1100 °C and 1300 °C in a pressurized furnace are evaluated, with particular reference to the binding energy region above 402 eV. The spectra for the feed coals were broadly similar to those reported previously for bituminous coals, in that pyrrolic nitrogen was the dominant functional form in each case. A minor component between 403 and 404.5 eV was assigned to ammonium nitrogen in liberated mineral matter. The N 1s spectra for the chars were also broadly similar to those expected for pyrolysis under intermediate residence time conditions, in that the proportion of pyrrolic nitrogen was no more than half that for the feed coal. Intensity in the 402-404.5 eV region was more consistent with N-O species formed post-pyrolysis than similar species formed as intermediates during pyrolysis.