Oxygen Reduction on Ag(100) in Alkaline Solutions?A Theoretical Study

LEANDRO MOREIRA DE CAMPOS PINTO; WOLFGANG SCHMICKLER; FERNANDA JUAREZ; ALEKSEJ GODULJAN; ELIZABETH SANTOS

Chemphyschem

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2016 vol. 17 p. 500 - 505

1439-4235

Silver is much more reactive to oxygen than gold; nevertheless,in alkaline solutions, the rates of oxygen reduction onboth metals are similar. To explain this phenomenon, the first,rate-determining step of oxygen reduction on Ag(100) is determinedby a combination of DFT, molecular dynamics, and electrocatalysistheory. In vacuum, oxygen is adsorbed on Ag(100),but in the electrochemical environment, the adsorption energyis offset by the loss of hydration energy as the molecule approachesthe surface. As a result, the first electron transfershould take place in an outer-sphere mode. Previously, thesame mechanism for oxygen reduction on Au(100) has beenpredicted, and these calculations have been repeated by usinga more advanced version of the electrocatalysis theory discussedherein to confirm previous conclusions. The theoreticalresults compare well with experimental data.