Boosting oxygen evolution reaction by activation of lattice‐oxygen sites in layered Ruddlesden‐Popper oxide

Abstract

Emerging anionic redox chemistry presents new opportunities for enhancing oxygen evolution reaction (OER) activity considering that lattice-oxygen oxidation mechanism (LOM) could bypass thermodynamic limitation of conventional metal-ion participation mechanism. Thus, finding an effective method to activate lattice-oxygen in metal oxides is highly attractive for designing efficient OER electrocatalysts. Here, we discover that the lattice-oxygen sites in Ruddlesden-Popper (RP) crystal structure can be activated, leading to a new class of extremely active OER catalyst. As a proof-of-concept, the RP Sr3(Co0.8Fe0.1Nb0.1)2O7-δ (RP-SCFN) oxide exhibits outstanding OER activity (eg, 334 mV at 10 mA cm−2 in 0.1 M KOH), which is significantly higher than that of the simple SrCo0.8Fe0.1Nb0.1O3-δ perovskite and benchmark RuO2. Combined density functional theory and X-ray absorption spectroscopy studies demonstrate that RP-SCFN follows the LOM under OER condition, and the activated lattice oxygen sites triggered by high covalency of metal-oxygen bonds are the origin of the high catalytic activity. Show more