Tuning TiO2/Co3O4 Nano-interface for bridging photo- and plasma-catalytic reactive oxygen species generation

Photo-plasma catalysis, combining the controllability of photocatalysis with the high reactivity of plasma, presents a promising platform for reactive oxygen species (ROSs) generation. However, efficient coupling of photocatalysis and plasma requires interfaces that integrate multiple catalytic functions to reconcile differences between the two processes. Herein, we report the tuning of the TiO 2 /Co 3 O 4 nano-interface for efficient photo-plasma catalytic ROS generation by loading a Co 3 O 4 nanozyme onto a surface-disordered TiO 2 photocatalyst. For bisphenol A (BPA) removal, the composite catalyst achieves a degradation rate that is 17.3-fold and 12.6-fold higher than those of plasma and photocatalysis alone, respectively. Combined ROS scavenging and probe analyses reveal that the enhanced bisphenol A removal is directly related to the efficient singlet oxygen ( 1 O 2 ). Further mechanistic analyses suggest that the yield of 1 O 2 is linked to the conversion of superoxide radicals (•O 2 − ). The heterogeneous nano-interface serves as the key reaction center. Specifically, surface disorder and heterojunction-driven electron accumulation promote •O 2 − generation via photocatalytic O 2 reduction on TiO 2 , while holes in Co 3 O 4 oxidize plasma-generated H 2 O 2 to •O 2 − through a sustained Co 3+ /Co 2+ redox cycle. Compared with TiO 2 /Fe 2 O 3 and TiO 2 /CuO, TiO 2 /Co 3 O 4 exhibits superior photo-plasma catalytic performance due to the more efficient conversion between H 2 O 2 and •O 2 − enabled by the stable Co 3+ /Co 2+ redox cycle. This work provides a general paradigm for developing interfacial reaction centers in catalysts to improve coupled catalytic ROS generation.