Electrochemical promotion of the water‐gas shift reaction on Pt/YSZ

S. SOUENTIE; L. LIZARRAGA; J.L. VALVERDE; P. VERNOUX

Chania, Creta

Simposio; 9th European Symposium on Electrochemical Engineering; 2011

Working Party on Electrochemical Engineering (WPEE) of the European Federation of Chemical Engineering (EFCE).

The electrochemical promotion of the water-gas shift reaction for H2 production was investigated in a Pt/YSZ/Pt fuel-cell type electrocatalytic reactor at 350ºC, under ratio values from 2.85 to 31. Positive polarization application (+2.5 V), i.e. O2- species supply to the catalyst surface, produced a small decrease in the catalytic reaction rate, while negative potential application (-1.5 V) resulted in a pronounced rate increase, up to 200%, with apparent Faradaic efficiency values up to 110. The increase of the rate upon negative polarization was partially attributed to the reduction of the YSZ surface and formation of active sites for water activation and dissociation, but mainly to the weakening of the Pt-CO bond strength due to Oδ- ions pumping from the catalyst surface and the concomitant decrease on Pt work function.