Porous LaCo_1–xNi_xO_3−δNanostructures as an Efficient Electrocatalyst for Water Oxidation and for a Zinc–Air Battery

Abstract

Perovskites have emerged as promising earth-abundant alternatives to precious metals for catalyzing the oxygen evolution reaction (OER). Herein, we report the synthesis of a series of porous perovskite nanostructures, LaCo0.97O3-δ, with systematic Ni substitution in Co octahedral sites. Their electrocatalytic activity during the water oxidation reaction was studied in alkaline electrolytes. The electrocatalytic OER activity and stability of the perovskite nanostructure was evaluated using the rotating disk electrode technique. We show that the progressive replacement of Co by Ni in the LaCo0.97O3-δ perovskite structure greatly altered the electrocatalytic activity and that the La(Co0.71Ni0.25)0.96O3-δ composition exhibited the lowest OER overpotential of 324 and 265 mV at 10 mA cm(-2) in 0.1 M KOH and 1 M KOH, respectively. This value was much lower than that of the noble metal catalysts, IrO2, Ru/C, and Pt/C. Furthermore, the La(Co0.71Ni0.25)0.96O3-δ nanostructure showed outstanding electrode stability, with no observable decrease in performance up to 114th cycle in the auxiliary linear sweep voltammetry that lasted for 10 h in chronoamperometry studies. The excellent oxygen evolution activity of the La(Co0.71Ni0.25)0.96O3-δ perovskite nanostructure can be attributed to its intrinsic structure, interconnected particle arrangement, and unique redox characteristics. The enhanced intrinsic electrocatalytic activity of the La(Co0.71Ni0.25)0.96O3-δ catalyst was correlated with several parameters, such as the electrochemical surface area, the roughness factor, and the turnover frequency, with respect to variation in the transition metals of the perovskite structure. Subsequently, La(Co0.71Ni0.25)0.96O3-δ was utilized as the air cathode in a zinc-air battery application.

Recent Advances in Materials and Design of Electrochemically Rechargeable Zinc–Air Batteries

“…The perovskite electrocatalysts with the size of 50 nm showed superior activity and stability for both ORR and OER with less than 5% H 2 O 2 yield. Other than reducing the particle size alone, Vignesh et al synthesized 1D porous La(Co 0.71 Ni 0.25 ) 0.96 O 3−δ by electrospinning and the systematic Ni substitution of Co at octahedral sites . Bu et al also used electrospinning to produce mesoporous nanofibers of PrBa 0.5 Sr 0.5 Co 2− x Fe x O 5+δ , which has the well‐controlled B‐site metal ratio and a surface area (≈20 m 2 g −1 ) .…”

Directly Electrodeposited Cobalt Sulfide Nanosheets as Advanced Catalyst for Oxygen Evolution Reaction

“…The high‐resolution XPS spectra of Co 2p and S 2p regions are shown in Figure b and Figure c. In Co 2p region, the peaks at 779.8 and 780.7 eV can be assigned to Co 2p 3/2 , while the peaks at 794.8 and 796.5 eV correspond to Co 2p 1/2 . Another two peaks at 785.9 and 802.3 eV can be sequentially attributed to the satellite peaks of Co 2p 3/2 and Co 2p 1/2 .…”

Hollow‐Structured Metal Oxides as Oxygen‐Related Catalysts

“…[45] Typical double perovskites (AA′B 2 O 5+δ ) have stable structure and high catalytic activity for OER due to proper O p-band center position. [52] Copyright 2016, American Chemical Society. 5 [57] Copyright 2015, The Royal Society of Chemistry.…”

“…This is because the amorphous surface is favored in the absorption of oxygen species and fast dissociation of intermediates. [52] The excellent OER activity can be attributed to its intrinsic structure, interconnected particle arrangement and unique redox characteristics. Hollow nanofibers of various cation-ordered PrBa 0.5 Sr 0.5 Co 2−x Fe x O 5+δ have been successfully prepared via electrospinning method (TEM and model images in Figure 3d).…”