Investigation of copper oxidation states in plasmonic nanomaterials by XAS and Raman spectroscopy.

Plasmonic core–shell-isolated nanoparticles are promising nanoplatforms for photocatalysis and for low detection analysis. This paper describes the characterization of a 2,2′-bipyridine phosphonate functionalized Ag@TiO2 nanocomposite which complexes copper ions by enhanced Raman spectroscopy and X-ray absorption (XANES and EXAFS). We distinguished Cu(I) from Cu(II) complexes using shell-isolated nanoparticle enhanced Raman (SHINERS) combined with XAS spectroscopy.