Oxygen-vacancy abundant electrospun Co-doped Ruddlesden-Popper perovskite catalysts for peroxymonosulfate activation and Rhodamine B degradation

Abstract

The versatility of perovskite crystal structures has allowed their application in persulfate-based advanced oxidation process (PS-AOP). In this study, novel agglomerated-free Ruddlesden-Popper (RP)-type perovskite catalysts were fabricated via electrospinning and subsequent annealing. Structure modulation strategy was implemented by a moderate Co-substitution of relatively inert Cu at B site of RP-type La2CuO4. The performances of Co-doped perovskites (Cox-LC1-xO) for peroxymonosulfate activation and Rhodamine B (RhB) removal were investigated. Co displacement altered the Cox-LC1-xO compositions, increased the concentration of oxygen vacancies (OVs) and accelerated the electron transfer, thereby causing complementary effects on catalytic activities. The abundant OVs governed the production of reactive oxygen species (ROS) by regulating the cationic redox cycle and decreasing the energy barrier for PMS activation. In particular, OVs energized lattice oxygen, allowing RhB degradation by Co0.5-LC0.5O via the 1O2-dominant non-radical pathway. Co0.5-LC0.5O outperformed other Cox-LC1-xO catalysts with regard to RhB removal efficiency (∼98% within 30 min) and reaction kinetics (k = 0.552 min−1). Besides, Co0.5-LC0.5O exhibited decent reusability, wide pH range (4.0–8.5), and saline adaptation. These findings may facilitate the design of analogous peroxymonosulfate catalysts for wastewater reclamation.