Enhanced OER Performance and Dynamic Transition of Surface Reconstruction in LaNiO₃ Thin Films with Nanoparticles Decoration

Abstract

In an electrocatalytic process, the cognition of the active phase in a catalyst has been regarded as one of the most vital issues, which not only boosts the fundamental understanding of the reaction procedure but also guides the engineering and design for further promising catalysts. Here, based on the oxygen evolution reaction (OER), the stepwise evolution of the dominant active phase is demonstrated in the LaNiO3 (LNO) catalyst once the single‐crystal thin film is decorated by LNO nanoparticles. It is found that the OER performance can be dramatically improved by this decoration, and the catalytic current density at 1.65 V can be enhanced by ≈1000% via ≈109 cm−2 nanoparticle adhesion after extracting the contribution of surface enlargement. Most importantly, a transition of the active phase from LNO to NiOOH via surface reconstruction with the density of LNO nanoparticles is demonstrated. Several mechanisms in terms of this active phase transition are discussed involving lattice orientation‐induced change of the surface energy profile, the lattice oxygen participation, and the A/B‐site ions leaching during OER cycles. This study suggests that the active phases in transition metal‐based OER catalysts can transform with morphology, which should be corresponding to distinct engineering strategies.

Enhanced OER Performance through Electronic Structure Engineering in Artificial LaNiO3/SrRuO3 Superlattices

“…We found that the SL of n = 1 obtained the largest interface strain displays the lowest overpotential of 0.72 V at 2 mA/cm 2 current density, and the current density of n = 1 reaches 1.95 mA/cm 2 at 1.65 V, which is 315% and 205% higher than that of the single-layer LNO and SRO films, respectively. Meanwhile, our experimental results compared with previous reports on LNO performance show that the OER catalytic activity of the superlattice is considerably superior to that of the single-layer LNO film (at the same voltage, our SL always has this higher current density). − …”

Bifunctional Electrocatalysts for Overall and Hybrid Water Splitting

“…Cyclic voltammetry (CV) is conducted by linear and cyclic scanning of potentials with a certain range, and the change caused by reconstruction could be signified by the recorded current responses or the shape of CV curves. 153,221,222 Zhang and coworkers revealed the atomic-scale evolution of NiS 2 , α-NiS, β-NiS, and Ni 3 S 4 during HER in 1.0 M KOH via CV and other operando characterization techniques. 143 Along with cyclic potential scanning, the reduction peaks for the three nickel sulfides gradually disappeared, indicative of their reduction reconstruction.…”

“…For example, low-crystallinity means relatively mediocre conductivity and abundant defects signify poor structural stability, which even lead to structure collapse. , In addition, the detached species during reconstruction may block the diaphragm and thus increase the internal resistance of the electrolyzer. It is therefore critical to monitor the electrochemical reconstruction process to unravel the activity origin and enrich the toolbox for electrocatalysts design toward efficient overall and hybrid water splitting. − …”

Atomic-layered metal–organic framework on NiFe LDH for enhanced electrocatalytic oxygen evolution reaction

“…[1][2][3] However, the sluggish anodic OER usually requires a large thermodynamic potential for the O-O bond formation owing to the four consecutive proton-assisted electron transfer processes, resulting in a high overpotential of the water electrolyzer. [4][5][6][7] Recently research efforts have been largely devoted to the development of highperformance OER electrocatalysts, such as noble-metal and their oxides, e.g. Ir/Ru and IrO 2 and RuO 2 , [8][9][10] but their wide application is limited by high cost.…”