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

Direct oxidation of formic acid to CO<inf>2</inf> using noble-metal-free La<inf>0.80</inf>Sr<inf>0.20</inf>CoO<inf>3</inf> is demonstrated in this study. The catalyst was able to oxidize HCOOH without any externally applied potential. The activity of La<inf>0.80</inf>Sr<inf>0.20</inf>CoO<inf>3</inf> is compared with that of Pt nanoparticles. It is observed that the amount of CO<inf>2</inf> generated using La<inf>0.80</inf>Sr<inf>0.20</inf>CoO<inf>3</inf> 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 La<inf>0.80</inf>Sr<inf>0.20</inf>CoO<inf>3</inf> in the catalytic effect. The Sr ions were not found to have any appreciable role in the dissociation step. Weak binding of CO<inf>2</inf> involving energy changes of the order of −1 kcal/mol indicated the ease of CO<inf>2</inf> desorption from the catalyst surface, thus making the catalyst highly active for electrochemical HCOOH oxidation.