Unraveling detailed reaction pathways for oxygen reduction reaction (ORR) on metal surfaces has been a long-standing challenge in the field of electrocatalysis. In this presentation, we will discuss mechanistic insights on ORR on polycrystalline Au surface obtained by using in situ surface enhanced IR absorption spectroscopy (SEIRAS) that was further aided by ab initio DFT calculations in assigning observed reaction intermediates. With these reaction intermediates assigned, we were able to work out for the first time the ORR reaction pathways on Au in both 0.1M HClO4 and 0.1M H2SO4 supporting electrolytes. Proton transfer is likely the most important reaction-control step. Therefore, any mechanism that enhances proton transfer will probably enhance the ORR. Moreover, experimental evidence suggests that 3-fold ClO4� adsorption helps stabilize hydronium on the surface and thus enhances the proton transfer reaction. In contrast, strong adsorption of HSO4� seems to do the opposite.

Insights on oxygen reduction reaction on Au polycrystalline surface as seen by in situ surface enhanced IR absorption spectroscopy

244th National Meeting (2012)

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