A single-source precursor route to a Cu/V₂O₅ composites as surface-enhanced Raman scattering substrates and catalysts for cross coupling

A Cu/V₂O₅ composite was obtained via a simple and time-saving microwave-assisted reduction method from a single-source precursor, copper vanadate. This composite exhibited excellent SERS sensitivity and reproducibility for both Rhodamine 6G (1.0 × 10^-7 M) and 4-mercaptobenzoic acid (1.0 × 10^-5 M) probe molecules, with the enhancement factor of 1.9 × 10⁶ for Rhodamine 6G. The Lewis acid-base properties of V₂O₅ help improve the chemical enhancement of SERS via Lewis acid-base interaction. Furthermore, the Cu/V ₂O₅ composite was also employed to catalyze C-N and C-C bond cross coupling of the Ullmann reaction. The results demonstrated that Cu/V₂O₅ catalysts had a better catalytic ability toward the C-N bond (yield of 92.5%) than the C-C bond (yield of 68.8%). This SERS-active composite was hopeful in monitoring the catalytic reactions with in situ SERS technology.