g-C3N4-based materials functionalized with Au, Ag, and Au-Ag: An XPS study

In the present contribution, x-ray photoelectron spectroscopy was used to characterize the surface composition and elemental chemical states of graphitic carbon nitride (g-C3N4) materials decorated with highly dispersed noble metals (Au, Ag, or Au + Ag). Samples were prepared through electrophoretic deposition of g-C3N4 on fluorine-doped tin oxide substrates and annealed at 500 °C in Ar. The resulting systems were subsequently functionalized by radio frequency-sputtering and finally annealed again under an Ar atmosphere. Material structural and morphological characterization revealed an intimate contact of the introduced noble metals with the underlying g-C3N4 matrix. Survey spectra as well as detailed scans for C 1s, N 1s, O 1s, Au 4f, Ag 3d, and Sn 3d regions are presented and critically discussed. The obtained results evidence the presence of highly defective carbon nitride matrices functionalized by low-sized Au nanoaggregates, atomically dispersed Ag, or partially alloyed Au-Ag core/shell nanoparticles.