Comparative Study of the Electrochemical Promotion of CO2 Hydrogenation over Ru‐Supported Catalysts using Electronegative and Electropositive Promoters
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Media type:
E-Article
Title:
Comparative Study of the Electrochemical Promotion of CO2 Hydrogenation over Ru‐Supported Catalysts using Electronegative and Electropositive Promoters
Description:
<jats:title>Abstract</jats:title><jats:p>The kinetics and the electrochemical promotion of the hydrogenation of CO<jats:sub>2</jats:sub> over Ru‐catalyst electrodes deposited on yttria‐stabilized zirconia (YSZ) and (Na<jats:sup>+</jats:sup>)‐β“‐Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> solid electrolytes are investigated at temperatures between 200 and 340 °C and pressures up to 5 bar. In the case of both the O<jats:sup>2−</jats:sup> conductor (YSZ) and the Na<jats:sup>+</jats:sup> conductor (β”‐Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>), the selectivity for CH<jats:sub>4</jats:sub> production is enhanced significantly when using a positive potential by supplying of O<jats:sup>2−</jats:sup> to, or removal of Na<jats:sup>+</jats:sup> from, the catalyst surface. The opposite effect is observed when using a negative applied potential, which suppresses CH<jats:sub>4</jats:sub> formation and enhances the production of CO through the reverse water–gas shift reaction. However, at low Na coverage, and under reducing conditions, both methanation and H<jats:sub>2</jats:sub> production are promoted by the application of a negative potential. The observed electrochemical promotion behavior in conjunction with the reaction kinetics is consistent with the rules of electrochemical and chemical promotion.</jats:p>