(530i) In-Situ Surface Plasmon Resonance Study On Methanol Oxidation On Platinum Nanoparticles

Surface plasmon resonance (SPR) is recognized as a label-free and direct technique for sensitive chemical and biological sensing. Here we present an in-situ SPR study on electrochemical heterogeneous catalysis in order to evaluate the possible use of a novel plasmonic substrate in catalytic mechanism studies with detection of reaction intermediates. The SPR substrate used in the study is prepared by a simple soft-lithography process using recordable digital versatile disc (DVD-R) as templates. Anatase titania or other metal oxide gratings can be easily replicated by using sol-gel processes. A 50 nm thick gold is finally sputtered on the templated grating. The values of the SPR sensitivity and the figure of merit (FOM) is determined to be 737 nm per refractive index unit (nm/RIU) and 73.1, respectively. For further electrochemical methanol oxidation study, platinum nanoparticles are electrochemically deposited on gold surface. Constant step voltage is applied from 0.00 to 1.00 V with 0.05 V of increment voltage in nitrogen purged methanol containing sulfuric acid electrolyte solution (0.05 M H₂SO₄ + 2.00 M CH₃OH) with chronoamperometry (CA) while optical probe is equipped to investigate the resonance peak position along the voltage change. Significant elevated peak shift (about 8 nm) is observed especially in low voltage region (from 0.00 to 0.55 V).