Sara Stolfi's doctoral activity focuses on the mechanistic study of reactions occurring at the solid/gas interface of heterogeneous catalysts, particularly graphitic carbon nitrides (g-C3N4). The main technique used is absorption spectroscopy in the soft X-ray range (soft-XAS), at ambient pressure and in operando conditions. The experiments are conducted in collaboration with APE HE bemline at Elettra Synchrotron, where a specially designed reaction cell is available.