Impact of Surface Defects on LaNiO₃ Perovskite Electrocatalysts for the Oxygen Evolution Reaction

Abstract

Perovskite oxides are regarded as promising electrocatalysts for water splitting due to their cost‐effectiveness, high efficiency and durability in the oxygen evolution reaction (OER). Despite these advantages, a fundamental understanding of how critical structural parameters of perovskite electrocatalysts influence their activity and stability is lacking. Here, we investigate the impact of structural defects on OER performance for representative LaNiO3 perovskite electrocatalysts. Hydrogen reduction of 700 °C calcined LaNiO3 induces a high density of surface oxygen vacancies, and confers significantly enhanced OER activity and stability compared to unreduced LaNiO3; the former exhibit a low onset overpotential of 380 mV at 10 mA cm−2 and a small Tafel slope of 70.8 mV dec−1. Oxygen vacancy formation is accompanied by mixed Ni2+/Ni3+ valence states, which quantum‐chemical DFT calculations reveal modify the perovskite electronic structure. Further, it reveals that the formation of oxygen vacancies is thermodynamically more favourable on the surface than in the bulk; it increases the electronic conductivity of reduced LaNiO3 in accordance with the enhanced OER activity that is observed.

Direct O–O Coupling Promoted the Oxygen Evolution Reaction by Dual Active Sites from Ag/LaNiO3 Interfaces

“…In contrast, η 10 increased to 322 mV (Ag/LNO-0.3) and 343 mV (Ag/LNO-0.5) as x increased to 0.3 and 0.5, respectively. The trend in the OER performance of Ag/LNO- x electrocatalysts was not correlated with the amount of the additional NiO phase in the Ag/LNO- x , and a recent report also showed that NiO exhibited a much higher overpotential for OER compared to the pristine LNO . Therefore, the existence of NiO was not considered for analyzing the improvement of the OER performance.…”

“…The trend in the OER performance of Ag/LNO-x electrocatalysts was not correlated with the amount of the additional NiO phase in the Ag/LNO-x, and a recent report also showed that NiO exhibited a much higher overpotential for OER compared to the pristine LNO. 55 Therefore, the existence of NiO was not considered for analyzing the improvement of the OER performance. The activity comparison of the Ag/LNO-x electrocatalysts suggested that an appropriate amount of Ag nanoparticles would enhance the OER electrocatalytic activity through the synergetic effect between Ag nanoparticles and the LNO surface.…”

A comprehensive review of cathode materials for Na–air batteries

“…However, ternary metal oxides such as ABO 3 (perovskite) 63 and AB 2 O 4 (spinel) [93][94][95] show better catalytic activity than binary metal oxides. This is due to the coexistence of multiple valences of metal cations causing intervalence charge transfer (IVCT), 118,119 and/or the formation of oxygen vacancies and structural defects in the system, 29,120,121 and these play an essential role in improving the catalytic efficiency. Detailed information on perovskite and spinel type materials and their electrochemical performances are summarised in Table 3.…”

Mastering the D-Band Center of Iron-Series Metal-Based Electrocatalysts for Enhanced Electrocatalytic Water Splitting

“…Shifting the d-band center by creating defects or improving vacancies is an effective way to regulate electronic and geometric structures because downshifting can aid the active intermediate desorption of active intermediates and upshifting promotes the adsorption of the active intermediates [ 89 , 90 , 91 , 92 ], leading to an enhancement in the reactivity of active sites, which significantly facilitates the activity of electrocatalytic water splitting.…”