A review on surface oxygen species in perovskite oxide catalysts for oxidation reactions: Toward rational catalyst design

ABO₃ Perovskite oxides have attracted considerable attention as oxidation catalysts due to their excellent thermal stability, redox flexibility, and tunable electronic structures. Among the key factors governing their catalytic performance, surface oxygen species, including adsorbed and lattice oxygen, play pivotal roles in determining activity and reaction mechanisms. Despite their recognized importance, the precise nature of their reactivity and mechanistic contributions remains under active debate, with conflicting interpretations across studies. This review aims to provide a comprehensive understanding of how surface oxygen species influence catalytic behavior. We examine their formation, reactivity, and mechanistic roles in perovskite-catalyzed oxidation reactions, focusing on CO, CH₄, NH₃, and volatile organic compounds. Recent experimental approaches, including post-treatment strategies, A/B-site stoichiometry tuning, and interfacial engineering, are discussed in terms of their impact on oxygen species distribution and electronic structure. Complementary density functional theory (DFT) studies are also reviewed, elucidating correlations between surface oxygen activity and electronic descriptors, such as oxygen vacancy formation energy, O 2p-band center, and orbital hybridization. Furthermore, we investigate advanced characterization techniques that enable identification and quantification of surface oxygen species under both static and reactive conditions. By integrating experimental and theoretical insights and reconciling diverse findings, this review provides a clearer understanding of the multifaceted roles of surface oxygen species and offers guidance for the rational design of high-performance perovskite-based oxidation catalysts.