The ability to efficiently oxidize small molecules containing C-C bonds (e.g. ethanol and ethylene glycol) is challenging at low temperature (i.e., < 80°C). It was previously shown that bimetallic catalysts (e.g. Pd-Au systems) have enhanced electrocatalytic activities for various organic reactions.¹ Moreover, an increased overall selectivity and turnover frequency for primary alcohol conversion to aldehydes has been reported after the addition of Au to Pd nanocrystals.² However dissociation of the C-C bonds is often incomplete and only undergoes a partial oxidation to intermediate product(s). Therefore, a breakthrough technology is required to overcome this obstacle at low temperature. One strategy is to tailor bimetallic catalysts for photo-electrochemical oxidation reactions by engineering the plasmonic response. For example, bimetallic Pd-Au nanostructures have been tuned to the visible portion of the solar spectrum for use as plasmonic H₂ sensors.³ We report the use of nanolithography patterned Pd-Au bimetallic catalysts for the photo-electrochemical oxidation of ethanol and ethylene glycol. We consider the effect of laser and solar-simulated excitations on nanostructured Pd-Au bimetallic electrodes fabricated on atomic layer deposited TiO₂ films coupled to a back contact.^4-5 The Pd-Au bimetallic electrodes with and without film-coupling are evaluated in parallel with discrete dipole approximation (DDA) modeling derived from doubly-periodic array simulations, which allows assessment of the absorption, scattering, and near-field enhancements. For select bimetallic configurations, we compare the selectivity and kinetics of the photo-electrochemical oxidation reactions and discuss the catalytic response driven by light excitation.

1. Lu, C.L.; Prasad, K. S.; Wu, H.L.; Ho, J.A.; Huang, M.H. JACS 2010, 132 (41), 14546-14553.
2. Enache, D. I.; Edwards, J. K.; Landon, P.; Solsona-Espriu, B.; Carley, A. F.; Herzing, A. A.; Watanabe, M.; Kiely, C. J.; Knight, D. W.; Hutchings, G. J. Science 2006, 311 (5759), 362-365.
3. Nugroho, F. A.; Iandolo, B.; Wagner, J. B.; Langhammer, C. ACS Nano 2016, 10 (2), 2871-9.
4. McClure, J. P.; Grew, K. N.; Das, N. C.; Chu, D.; Baker, D.; Strnad, N.; Gobrogge, E. MRS Advances 2017, 2 (55), 3397-3402.
5. Ciracì, C.; Chen, X.; Mock, J. J.; McGuire, F.; Liu, X.; Oh, S.-H.; Smith, D. R. Applied Physics Letters 2014, 104 (2), 023109.