Misconceptions in interpretation of nitrogen chemistry from x-ray photoelectron spectra

This perspective explores the complexity of nitrogen chemistry and its interpretation from high-resolution x-ray photoelectron spectra by examining metal-nitrogen-doped carbon systems used in many technological applications. Current understanding of factors contributing to nitrogen 1s photoelectron spectroscopic signature is reviewed, and limitations on assigning precise chemistries to individual spectral ranges are discussed. The importance of proper curve fitting of XPS spectra based on appropriate peak widths and shapes for correct data interpretation is highlighted. Appropriate peak fitting and chemical identification are critical to developing structure-to-property correlations for functional materials in which nitrogen chemistry plays a vital role.