SERS chemical enhancement of 2,4,5-trichlorophenoxyacetic acid absorbed on Au20, its Au-Ag and Au-Cu bimetallic clusters: a DFT study

The surface-enhanced Raman scattering (SERS) phenomenon of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) adsorbed on Au20 pyramidal cluster is studied by Density Functional Theory. All possible adsorption configurations between the adsorbate and clusters are evaluated vibrational assignments normal SERS spectra analyzed. result shows that most stable configuration formed interaction O13 (-COOH group) Au atom. activities 2,4,5-T 1:1 Au-Ag Au-Cu bimetallic also investigated. For clusters, substitution 1, 4 or 10 atoms Ag/Cu performed replacing respective number in 2 3 parallel layers cluster. While activity Au10Ag10 comparable to cluster, it remarkably higher than Au10Cu10 This observation explained molecule-to-cluster charge transfer process. obtained results hoped contribute better design SERS-based analytical sensors for mobile on-site applications.