Reduced graphene oxide encapsulated perovskite-type lanthanum cobalt oxide nanoparticles for efficient electrolysis of water to oxygen reactions (OER/ORR)

Developing high-performance non-precious electro-catalysts for water splitting reactions is important for energy conversion applications. In this study, reduced graphene oxide encapsulated perovskite-type lanthanum cobalt oxide nanoparticles (LaCoO3@rGO) have been fabricated as highly efficient electro-catalysts by ultra-sonication process for electrochemical oxygen evolution and reduction reac-tions (OER/ORR) in O2 - saturated alkaline medium (1.0 M KOH). The characterization techniques indi-cated that the targeted materials were formed with controlled support by rGO sheets to the nanoparticles. The LaCoO3@rGO nanocomposites show improved electro-catalytic performance to OER with lower over-potential (280 mV at n10) and Tafel slopes (104 mV/dec) compared with pure LaCoO3 electro-catalyst. The electro-chemical ORR reactions of the prepared electrodes were monitored by the rotating disk electrode (RDE) measurements. The LaCoO3@rGO electro-catalyst shows 4e-system in ORR at all potentials (i.e. from 0.2 V to 0.5 V), while LaCoO3 electro-catalyst shows 4e-system only at low potentials (i.e. 0.2 V and 0.3 V). Moreover, the stability of the electrodes was also tested by the chronoamperometry (CA) and cyclic stability measurements for the commercial purpose. Our research will open new windows for developing the non-precious electro-catalysts in clean energy applications.(c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

In this study, reduced graphene oxide encapsulated perovskite-type lanthanum cobalt oxide nanoparticles (LaCoO3@rGO) were synthesized as highly efficient electro-catalysts for electrochemical oxygen evolution and reduction reactions. The LaCoO3@rGO nanocomposites showed improved performance in oxygen evolution reaction with lower over-potential and Tafel slopes compared to pure LaCoO3 catalyst. The electrochemical oxygen reduction reaction showed better 4e-system behavior for LaCoO3@rGO catalyst at all potentials.