Oxygen Reduction Reaction on Pt(111): Effects of Bromide
Using the rotating ring-disk technique (RRDE) the oxygenreduction reaction (orr) was studied on the Pt(111) surface in thepresence of Br- anions. We found that the orr at the Pt(111) Bradinterface is always accompanied quantitatively by H2O2 oxidation currentson the ring electrode, implying that in the presence of Br- anions theorr does not proceed entirely through the 4e- reduction pathway, as inthe Br--free solution. We propose that strongly adsorbed Br- cansimultaneously suppress both the adsorption of the O2 molecule and theformation of pairs of platinum sites needed for the breaking of the O-Obond. Besides elucidating the effects of Brad, these studies also shedsome light on the role of OHad on the kinetics of the orr on the Pt(111)surface in solution free of Br anions. We have developed a theoreticalmodel and from simulations of I-E curves we propose two modes of actionof the OHad state on the kinetics of the orr on the Pt(111) surface: (i)OHad can block the adsorption of O2 on active platinum sites, i.e. theycompete for the same sites, and (ii) OHad can alter the adsorption energyof intermediates which are formed during the orr on the bare Pt sitesadjacent to the OHad.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Assistant Secretary for Energy Efficiency andRenewable Energy
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 895784
- Report Number(s):
- LBNL--42112
- Journal Information:
- Journal of Electroanalytical Chemistry, Journal Name: Journal of Electroanalytical Chemistry Journal Issue: 1 Vol. 467
- Country of Publication:
- United States
- Language:
- English
Similar Records
Surface segregation effects in electrocatalysis: Kinetics ofoxygen reduction reaction on polycrystalline Pt3Ni alloy surfaces
Anion adsorption, CO oxidation, and oxygen reduction reaction on a Au(100) surface: The pH effect