Insights into Pathway Selectivity during Anodic Formic Acid Oxidation over La1-xSrxCoO3

We report insights into the mechanism and pathway selectivity of anodic oxidation of HCOOH over La1-xSrxCoO3, which finds application in direct formic acid fuel cells, developed using density functional theory calculations. We analyzed three reaction routes for trans-HCOOH oxidation, viz., formate-mediated direct oxidation, carboxyl-mediated direct oxidation, and the indirect oxidation route. For cis-HCOOH, only one route, direct oxidation via dehydrogenation, was observed. Our results conclusively indicate that the indirect reaction route, which involves the formation of poisonous CO, is suppressed by highly stable surface intermediates; hence, this pathway is not feasible. The reaction takes place predominantly via surface isomerization of trans- to cis-HCOOH.

Automated summary

This study investigates the mechanism and pathway selectivity of anodic oxidation of HCOOH over La1-xSrxCoO3 using density functional theory calculations. The results indicate that the formate-mediated direct oxidation and carboxyl-mediated direct oxidation routes are not feasible, while the surface isomerization of trans- to cis-HCOOH is the dominant reaction pathway.