Surface enhanced photochemistry of p-nitrobenzoic acid on mixed silver-gold nanoparticles

CHED 1450

Fan Shi, fshi@linfield.edu, Brian D. Gilbert, and Rachel K. Kaneta, rkaneta@linfield.edu. Department of Chemistry, Linfield College, 190 SW Brumback St. Unit 3339, McMinnville, OR 97128
The surface-mediated photoreduction of p-nitrobenzoic acid (PNBA) has been observed on mixed AgxAu(100-x) nanoparticle coated surfaces. The AgxAu(100-x) nanoparticles were prepared by first preparing a “seed” colloid (Au or Ag), followed by reducing the Au or Ag onto the seed particle. Mixed AgxAu(100-x) nanoparticles were then bound to glass substrates via mercaptopropyl trimethoxy silane. The photoreduction of PNBA to azodibenzoic acid on the mixed nanoparticle slides was monitored using a 633 nm He-Ne laser, which was also used to initiate the reaction. We found that the mixed Ag/Au nanoparticle does enhance the SERS signal. Furthermore, larger fractions of Ag gave better SERS enhancement.