Enhanced Oxygen Evolution Electrocatalysis in Strained A-Site Cation Deficient LaNiO₃ Perovskite Thin Films

Abstract

As the BO6 octahedral structure in perovskite oxide is strongly linked with electronic behavior, it is actively studied for various fields such as metal–insulator transition, superconductivity, and so on. However, the research about the relationship between water-splitting activity and BO6 structure is largely lacking. Here, we report the oxygen evolution reaction (OER) of LaNiO3 (LNO) by changing the NiO6 structure using compositional change and strain. The 5 atom % La deficiency in LNO resulted in an increase of the NiONi bond angle and an expansion of bandwidth, enhancing the charge transfer ability. In-plane compressive strain derives the higher d z 2 orbital occupancy, leading to suitable metal–oxygen bond strength for OER. Because of the synergistic effect of A-site deficiency and compressive strain, the overpotential (η) of compressively strained L0.95NO film is reduced to 130 mV at j = 30 μA/cm2 compared with nonstrained LNO (η = 280 mV), indicating a significant enhancement in OER.

A General Strategy to Boost Electrocatalytic Nitrogen Reduction on Perovskite Oxides via the Oxygen Vacancies Derived from A‐Site Deficiency

“…As the concentration of A-site deficiency increased, the position of the main peak corresponding to (121) plane slightly shifted to higher angle, suggesting a lattice shrinkage, which could be probably attributed to the tilted FeO 6 octahedra to fill the extra space created by the La-site deficiency. [32] As a note, because more La-site deficiencies (i.e., 15% and even higher) in LF could produce an impurity phase of Fe 2 O 3 , here we limited the La-site deficiency to 10% for avoiding the effects of impurity phase on NRR activity. [33,34] Scanning electron microscopy (SEM) ( Figure S1, Supporting Information) and transmission electron microscopy (TEM) ( Figure S2, Supporting Information and Figure 1b-d) images showed typical morphologies of the LF, L 0.95 F, and L 0.9 F nanoparticles.…”

Application of X‐Ray Absorption Spectroscopy in Electrocatalytic Water Splitting and CO2 Reduction

“…[ 51–53 ] In addition, the orbital–lattice interaction derived from strained engineering and magnetic catalysts can be investigated via X‐ray linear dichroism (XLD) measurement. [ 54 ] Ex situ XAS can characterize the structural information of a catalyst before and after the electrocatalytic reaction, from which to indirectly predict possible change in the electrocatalytic reaction.…”

Bifunctional electrochemical properties of La0.8Sr0.2Co0.8M0.2O3−δ(M = Ni, Fe, Mn, and Cu): efficient elemental doping based on a structural and pH-dependent study

“…4,5 In response, extensive research efforts have been made to explore non-precious metal-based bifunctional catalysts for the OER/ORR with high performances. 6,7 Perovskite oxides (ABO 3 ) have the potential of being bifunctional catalysts or efficient oxygen electrodes due to their excellent oxygen mobility, low cost and their structures with atomic-level defects that play important roles in the OER/ORR. [8][9][10] One way to improve the OER/ORR of perovskite oxides is to increase their specific surface area and porosity of the catalysts, which have been reported to be beneficial for exposing more accessible active sites and facilitating the mass transfer and electron transfer during the OER/ORR processes.…”