Engineering Oxygen Vacancies into LaCoO₃ Perovskite for Efficient Electrocatalytic Oxygen Evolution

Abstract

Oxygen vacancies (OVs) can improve catalytic activities in oxygen evolution reaction (OER). Although considerable effort has been devoted to increasing the OVs concentration in electrocatalysts, limited OVs have been created by current techniques so far. Here, we, for the first time, engineered (i.e., created) abundant OVs into perovskites by element doping and plasma treatment. The results revealed that more OVs were manufactured by combination of Sr doping with Ar plasma treatment, leading to improved OER activity and high stability of LaCoO 3 perovskite. The La 1-x Sr x CoO 3-δ (x = 0.3) sample with Ar plasma treatment (denoted as Sr-0.3-p) showed high OER activity and stability due to the existence of rich OVs, which provided large amounts as well as high intrinsic activity of active sites in OER. The combination of two OV-creating techniques provides an efficient strategy to develop OV-rich catalysts for various applications.

Recent Progress of Vacancy Engineering for Electrochemical Energy Conversion Related Applications

“…Among the investigated ionic vacancies, oxygen vacancy has been widely applied to tune electrocatalytic properties due to the low formation energy of this kind of vacancy. [ 100–102,110 ] The previous studies have been proved that the introduced oxygen vacancies could decrease the electrical resistance efficiently and then benefit to enhance the catalytic performance for OER. [ 61a ] Moreover, it is important to elucidate the relationship between oxygen vacancy concentration and electrocatalytic performance for the design of efficient electrocatalysts.…”

Engineering of the d‐Band Center of Perovskite Cobaltite for Enhanced Electrocatalytic Oxygen Evolution

“…Perovskite oxides (ABO 3 ), which incorporate rare‐earth cations (A‐site) and transition metal cations (B‐site), have been recognized as potential alternatives noble‐metal electrocatalysts owing to its high ionic and structure flexibility . In previous studies, LaCoO 3 (LCO) was found to be a durable and active OER catalyst . Theoretical studies anticipated that the OER activity of the perovskite depends on the electronic structure of the transition metal.…”

Advanced Characterization Techniques for Identifying the Key Active Sites of Gas‐Involved Electrocatalysts

“…[ 96 ] Recently, the importance of OVs in perovskite oxide electrocatalysts was also addressed, [ 28 ] which act as active sites and hence improve intrinsic activity. [ 97 ] Mefford et al. substituted La 2+ with Sr 2+ in LaCoO 3 and investigated the influence of OVs and BO bond covalency on the electrocatalytic performance.…”