Boosting C3-alcohol electrooxidations by co-fueling with formic acid: A real-time quantitative nuclear magnetic resonance spectroelectrochemical study.

[Display omitted] • Co-fueling increases the current densities of C 3 -alcohols maximally by 9.9 times. • Product evolutions are recorded with in situ NMR monitoring. • Charge distributions are quantitatively analyzed with EC-NMR technique. • Co-fueling enhances the adsorption of –OH and the cleavage of C-C-C bonds. C 3 -alcohols can theoretically provide high current efficiencies in direct fuel cell applications because of their intrinsically large energy densities. However, during realistic reactions, molecular multiple carbon–carbon (C C C) bonds are hardly broken, severely reducing current efficiencies. Herein, directly with commercial Pt/C as the catalyst, the operation of co-fueling with formic acid significantly enhances the current efficiencies of two types of C 3 -alcohols, namely, isopropanol and 1,2-propanediol. Compared with the current densities of pure C 3 -alcohols, those of co-fueled C 3 -alcohols increase maximally by 9.9 times. The reason lies in the fact that the co-fueling design facilitates the breaking of C C C bonds, as elucidated by charge distributions that are obtained via electrochemical nuclear magnetic resonance analyses. Density-functional-theory computational results indicate that the generation of OH groups adsorbed on Pt surfaces is promoted in co-fueling experiments, reducing energy barriers for breaking progress. The co-fueling strategy is capable of optimizing C 3 -alcohol electrooxidations in direct fuel cells and deserves extensive study. [ABSTRACT FROM AUTHOR]