La0.80Sr0.20CoO3 as a noble-metal-free catalyst for the direct oxidation of formic acid under zero applied potential

Abstract

Direct oxidation of formic acid to CO2 using noble-metal-free La0.80Sr0.20CoO3 is demonstrated in this study. The catalyst was able to oxidize HCOOH without any externally applied potential. The activity of La0.80Sr0.20CoO3 is compared with that of Pt nanoparticles. It is observed that the amount of CO2 generated using La0.80Sr0.20CoO3 is five times higher than that generated with Pt nanoparticles. The experimental observations are supported by DFT calculations, which reveal the role of the lattice oxygen in La0.80Sr0.20CoO3 in the catalytic effect. The Sr ions were not found to have any appreciable role in the dissociation step. Weak binding of CO2 involving energy changes of the order of −1 kcal/mol indicated the ease of CO2 desorption from the catalyst surface, thus making the catalyst highly active for electrochemical HCOOH oxidation. Keywords: Formic acid, Electro-oxidation, Lattice oxygen, Perovskite, DFT