Quantitative and qualitative analysis of nitrogen species in carbon at the ppm level

Advanced carbon materials used for energy-related applications often contain nitrogen as a heteroatom, which can substantially influence their physical, chemical, and electronic properties. However, conventional analytical techniques for nitrogen environments provide limited compositional and structural information in high sensitivity, which significantly restricts rationalized materials design. Herein, we present the advanced temperature-programmed desorption (TPD) technique up to 2,100°C as a comprehensive analytical tool for chemical speciation in bulk nitrogen-doped carbon materials with record-high sensitivity. Employing complementary X-ray photoelectron spectroscopy, elemental analysis, and computational modeling, we discovered that the gas emission patterns can provide both compositional and structural information regarding nitrogen environments. Importantly, TPD enables the bulk quantification of nitrogen species at 10 ppm levels, which is two orders of magnitude more sensitive than conventional methods. Such an advanced characterization method provides a foundation for next-generation research, focusing on the structural design at the ppm level, and offers significant potential for industrial applications.