Self‐Assembled Ruddlesden–Popper/Perovskite Hybrid with Lattice‐Oxygen Activation as a Superior Oxygen Evolution Electrocatalyst

Abstract

The oxygen evolution reaction (OER) is pivotal in multiple gas‐involved energy conversion technologies, such as water splitting, rechargeable metal–air batteries, and CO2/N2 electrolysis. Emerging anion‐redox chemistry provides exciting opportunities for boosting catalytic activity, and thus mastering lattice‐oxygen activation of metal oxides and identifying the origins are crucial for the development of advanced catalysts. Here, a strategy to activate surface lattice‐oxygen sites for OER catalysis via constructing a Ruddlesden–Popper/perovskite hybrid, which is prepared by a facile one‐pot self‐assembly method, is developed. As a proof‐of‐concept, the unique hybrid catalyst (RP/P‐LSCF) consists of a dominated Ruddlesden–Popper phase LaSr3Co1.5Fe1.5O10‐δ (RP‐LSCF) and second perovskite phase La0.25Sr0.75Co0.5Fe0.5O3‐δ (P‐LSCF), displaying exceptional OER activity. The RP/P‐LSCF achieves 10 mA cm−2 at a low overpotential of only 324 mV in 0.1 m KOH, surpassing the benchmark RuO2 and various state‐of‐the‐art metal oxides ever reported for OER, while showing significantly higher activity and stability than single RP‐LSCF oxide. The high catalytic performance for RP/P‐LSCF is attributed to the strong metal–oxygen covalency and high oxygen‐ion diffusion rate resulting from the phase mixture, which likely triggers the surface lattice‐oxygen activation to participate in OER. The success of Ruddlesden–Popper/perovskite hybrid construction creates a new direction to design advanced catalysts for various energy applications.

Layered double hydroxide-based electrocatalysts for the oxygen evolution reaction: identification and tailoring of active sites, and superaerophobic nanoarray electrode assembly

“…In Fig. 1, some classical and popular electrocatalysts for the OER are summarized, including Ruddlesden-Popper oxides, [57][58][59][60] rock salt oxides, 61 rutiles, 62 high-entropy alloys, [63][64][65] perovskites, 66,67 metal oxides, 62,68-73 spinels 41,[74][75][76][77][78] and LDHs, 62,[79][80][81][82][83][84][85][86][87][88] from which it can be deduced that LDH species have shown the most outstanding OER performance, with small Tafel slopes and relatively low overpotentials at a given current density. Therefore, the use of LDHs for designing advanced OER electrocatalysts has attracted sufficient attention from researchers across the globe.…”

High‐Performance Perovskite Composite Electrocatalysts Enabled by Controllable Interface Engineering

“…[23][24][25] However, the fabrication of such composites involves sophisticated engineering of a perovskite, sometimes leveraging the solubility limit of elements within the perovskite structure, with methods to date having poor controllability and reproducibility. [23][24][25] We recently demonstrated several perovskite/perovskite composite systems, notably SP/SP, [26] SP/DP, [27] and SP/ RP [28,29] composites, found to form by self-assembly during calcination of a cation-stoichiometric perovskite precursor. Such self-assembly formation could potentially lead to better interfacial contact between the composite phases, improving the OER performance compared to single-phase counterparts.…”

“…However, it remains unclear whether the enhanced performance arises solely as a result of interface engineering, and how this contributes to OER enhancement, or if this enhancement has some contribution as a result of the compositional variation of phases from their single-phase counterparts in the perovskite-based composite, where composition is found to depend on synthesis conditions. [26][27][28][29] Here, we report a cation deficiency-promoted phase separation method for the strategic in situ formation of strongly interacting dual-phase perovskite oxide composites, with the ability to achieve accurate control over the composition, structure, and content of the component phases. Such a well-designed composite system serves as a platform to explore the origin of catalytic enhancement on perovskite composite catalysts, by which we demonstrate incontrovertible evidence supporting the key role played by the interfacial interaction of the composite catalysts in facilitating the oxygen ionic transport to enhance the lattice-oxygen participated OER kinetics.…”

Oxygen evolution reaction activity and underlying mechanism of perovskite electrocatalysts at different pH

“…lattice oxygen evolution reaction, LOER). 1,6,[21][22][23][24][25][26][27][28][29] The LOER involves a dynamically changing catalyst surface as it interacts with the electrolyte, and it can potentially lead to perovskite metal cation dissolution. 1,6,25,[30][31][32] Likewise, the prominence of LOER has recently been highlighted to additionally elucidate the OER mechanism of transition metal oxide catalysts.…”