Synergy of Oxygen-Deficient LaFeO_3−δ and N-Doped Reduced Graphene Oxide in Oxygen Reduction Reaction in Alkaline Solutions

Abstract

The development of low-cost and efficient electrocatalysts for oxygen reduction reaction (ORR) is of prime importance to the emerging renewable energy technologies. Herein, a series of LaFeO 3−δ /NrGO-x (x = 10, 20, and 25) hybrid materials have been synthesized via a facile strategy that enhanced ORR performances in alkaline solutions owing to the strong coupling effect between defect-rich LaFeO 3−δ perovskite nanoparticles and N-doped reduced graphene oxide (NrGO) nanosheets. Among the oxygen-deficient perovskites/carbon hybrids, LFO/NrGO (LaFeO 3−δ /NrGO-20) demonstrates relatively excellent ORR catalytic activity. The Tafel slope of LFO/NrGO is lower than that of Pt/C (20 wt %). This remarkable improvement is largely correlated to the presence of surface oxygen vacancies and the distortion of [FeO 6 ] unit. On the other hand, the excellent durability of the LFO/NrGO hybrid mainly results from the strong interaction between LaFeO 3−δ nanoparticles and NrGO nanosheets. This work highlights the importance of regulating the synergy of perovskites/carbon hybrids as an effective strategy for boosting the ORR electrocatalytic activity for applications in oxygen-related energy storage and conversion processes.

Compositional and Morphology Optimization to Boost the Bifunctionality of Perovskite Oxygen Electrocatalysts

“…We should mention that, to compare the intrinsic activity of these compositions, the perovskite powder is not mixed with carbon. Though the perovskite/carbon composite may generate high activity, ,− the intrinsic activity trend may be greatly influenced by the introduction of carbon. Figure b shows typical polarization curves of LaNi x Mn 1– x O 3 electrodes by LSV at 5 mV s –1 and 1600 rpm in the OER region.…”