Activity Trends for the Selective Oxidation of 2-Propanol to Acetone on Noble Metal Electrodes in Alkaline Electrolyte
Abstrakt
Fuel cells based on 2-propanol can be used to produce electricity utilizing the hydrogen stored in liquid organic hydrogen carriers. While the focus has previously been on acidic media, where only platinum-based electrodes are active, we explore here the oxidation of 2-propanol in alkaline solutions on different noble metal electrodes.
Using experimental and computational methods, we find that the reaction is selective to acetone, whereas C-C bond breaking and the formation of adsorbed CO do not take place. The onset potential increases along the series Rh < Pt < Pd < Au, a trend that correlates with the adsorption energy of acetone on the respective surfaces.
The oxidation rate decays under potentiostatic conditions due to the progressive accumulation of acetone at the surface. At high overpotentials, the reaction is limited by oxide formation.
Given that alkaline systems are not restricted to exclusively platinum-based electrodes, a broader range of materials may be found that act as anodes for efficient 2-propanol fuel cells.