ELECTROREDUCTION OF CO 2 ON La 0.5 Ba 0.5 CoO 3 PEROVSKITES

VILDOSOLA V.; J.F ZAPATA; VIVA F. A.; BARRAL M. A.

Congreso; XXIX International Materials Research Congress; 2021

The CO2 reduction reaction is a versatile strategy to approach global climate change by converting excess CO2 in the atmosphere into useful raw materials. Different types of homogeneous and heterogeneous catalysts have been developed for this purpose. However, stable and inexpensive materials that achieve efficient reduction of CO2 in water with high selectivity of their products at low overpotential remain lacking. In this work, we focus on La0.5Ba0.5CoO3 perovskite, and perform cyclic voltammetry experiments in a three-electrode cell using 0.1 M KHCO3 as electrolyte saturated with CO2. The electrochemical analysis showed that the catalyst used reduces CO2 to CO with an efficiency of 29% at -1.2 V vs SHE, and to HCOOH with an efficiency of 30% at -0.9 V vs SHE. In addition, we perform ab-initio calculations based on density functional theory that support the experimental results. In particular, we studied the absorption of CO2 in the different terminations of the orientations (001) and (110) of La0.5Ba0.5CoO3 and its subsequent protonation to *COOH, which proved to be an essential intermediate in the reduction of CO2. The theoretical study allowed us to propose reaction paths towards the formation of CO and HCOOH, from which we obtained -0.92 V and -0.82 V vs SHE, respectively, as the minimum external potentials values. These are in high agreement with the experimental data. The experimental results and the support of the theoretical study indicate that the La0.5Ba0.5CoO3 perovskite catalyst shows interesting efficiencies for the conversion into CO and HCOOH at the corresponding potentials.