Permanent electrochemical promotion of C3H8 oxidation over thin sputtered Pt films

S. SOUENTIE; L. LIZARRAGA; E.I. PAPAIOANNOU; C.G. VAYENAS; P. VERNOUX

ELECTROCHEMISTRY COMMUNICATIONS

ELSEVIER SCIENCE INC

Lugar: Nueva York; Año: 2010 vol. 12 p. 1133 - 1135

1388-2481

The effect of "permanent electrochemical promotion of catalysis" (P-EPOC) was studied for the first time in the catalytic deep oxidation of C3H8 over a thin (similar to 150 nm) sputtered Pt film on YSZ, under excess of oxygen at 350 degrees C. Short positive potential application (+ 1 V) resulted in a 5.6-fold increase of the catalytic rate, where C3H8 conversion reached 33%, while the apparent Faradaic efficiency was similar to 330. After positive current interruption the catalytic rate remained in a highly active steady-state, determined by the total charge of the anodic polarization step. Restoration of the catalytic activity to the initial value occurred only by a similar negative potential imposition. This new stable steady-state after current interruption can be interpreted by storage of a non-reactive oxygen species upon anodic polarization at the proximity of the Pt/YSZ interface and subsequent enhanced migration of spillover O delta- species from the electrolyte support to the Pt/gas interface under open-circuit conditions.