Preparation of a Stable Cr₂O₃/Cu/TiO₂ Plasmonic Photocatalyst for Selective Alcohol Oxidation under Visible Light Irradiation (λ>600 nm)

Copper (Cu) nanoparticles (NPs) loaded on titanium(IV) oxide (TiO 2 ) exhibit an extinction at about λ=580 nm because of surface plasmon resonance (SPR); however, they rapidly lose their its SPR when exposed to air. In order to stabilize the Cu NPs, a multi‐step photodeposition method was used to introduce chromium, which resulted in successful synthesis of a Cr 2 O 3 /Cu/TiO 2 sample that exhibited extinction even when exposed to air. Transmission electron microscopy, scanning transmission electron microscopy, X‐ray photoelectron spectroscopy and UV‐vis spectroscopy were utilized to analyze the Cu/TiO 2 and Cr 2 O 3 /Cu/TiO 2 samples with a focus on SPR of the nanoparticles and state of the Cu species. The prepared Cr 2 O 3 /Cu/TiO 2 samples acted as plasmonic photocatalysts in oxidation of 2‐propanol under aerated conditions and visible light irradiation. Expandability of the Cr 2 O 3 /Cu/TiO 2 plasmonic photocatalyst was also investigated, and the results suggested the potential of a Cu‐based plasmonic photocatalyst working under irradiation of visible light.