Vertical Growth of Porous Perovskite Nanoarrays on Nickel Foam for Efficient Oxygen Evolution Reaction

Abstract

Perovskite oxides possess high intrinsic activity toward oxygen evolution reaction (OER), while their catalytic activities have been restricted by the low surface area and poor conductivity. Herein, we report binder-free LaCoO3 perovskite nanosheets vertically grown on the nickel foam as an OER catalyst with enhanced performance and stability in alkaline electrolytes. The proposed catalyst displays an outstanding performance to achieve the current density of 10 mA cm–2 at the overpotential of 342 mV, while 390 mV is required for the bulk LaCoO3 prepared by conventional methods. The enhanced OER activity is mainly because the nanosheet structures have increased surface areas and enhanced conductivity and charge transfer. Moreover, the porous structure formed by vertically aligned nanosheets increases surface wettability, which enables the rapid dissipation of gas bubbles along with excellent durability. This work proposes an approach to unlocking the high intrinsic activity of perovskites for OER.

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“…The first‐row transition metals, such as Ni, Fe, Co, have been demonstrated with good hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances. [ 14–22 ] In particular, Ni alloys with other transition metals have received extensive attention due to their excellent HER/OER activities and stability under harsh alkaline conditions. [ 15–17,19,20 ] Ni alloyed with Mo is a well‐known non‐noble metal‐based electrocatalyst for HER under alkaline condition.…”

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“…To address these limitations, fabricating perovskite oxides with nanoporous morphology and enlarged specific surfaces is an effective approach. 27,91 For example, the integration LaCoO 3 nanosheets with conductive nickel foam through hydrothermal treatment and annealing exhibited significantly improved OER performance ( Figure 2D,E). 27 Optimizing the composition by changing cations in the A and/or B site as well as doping with non-oxygen anion can further optimize the composition with enhanced activity.…”

“…However, the limited surface area and poor conductivity have restricted their catalytic performance. To address these limitations, fabricating perovskite oxides with nanoporous morphology and enlarged specific surfaces is an effective approach 27,91 . For example, the integration LaCoO 3 nanosheets with conductive nickel foam through hydrothermal treatment and annealing exhibited significantly improved OER performance (Figure 2D,E).…”

“…E, SEM images of LaCoO 3 /NF at different magnifications. Reproduced with permission: Copyright 2020, American Chemical Society 27 . F, TEM image of NiFe nanosheets (scale bar = 50 nm), and (G) Polarization curves for OER.…”

“…For example, the integration LaCoO 3 nanosheets with conductive nickel foam through hydrothermal treatment and annealing exhibited significantly improved OER performance (Figure 2D,E). 27 Optimizing the composition by changing cations in the A and/or B site as well as doping with non‐oxygen anion can further optimize the composition with enhanced activity 92 . To this end, multi‐metallic perovskites such as Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCF), SrNb 0.1 Co 0.7 Fe 0.2 O 3‐δ and La 0.5 Ba 0.25 Sr 0.25 CoO 2.9–δ F 0.1 have been reported as advanced catalysts with remarkable activity 28,57,93 .…”