Wettability controlled photocatalytic reactive oxygen generation and Klebsiella pneumoniae inactivation over triphase systems

Antibacterial technology based on photo-generated reactive oxygen species (ROS) represents a promising strategy for antibiotic-resistant bacteria inactivation, but often results in poor activity due to the limited O-2 solubility in traditional water-catalyst diphase system. In this work, we develop an air-water-catalyst triphase system to explore the superiority of air phase-supplied O-2 for the enhancement of ROS generation and Klebsiella pneumoniae (KPN) inactivation efficiencies. Using P25-TiO2 as model photocatalysts, we demonstrate that Wenzel-Cassie coexistent wetting state is the most conducive for photocatalytic ROS generation, offering a H2O2 generation rate of 1003 +/- 52 mu M h(-1), which is 18 times higher than corresponding diphase system. It also affords an over two orders of magnitude reduced KPN colony concentration within 30 min irradiation, achieving over 99 % light-triggered removal efficiency. The advantages of triphase system for photocatalytic bacterial inactivation will inspire the development of efficient photocatalytic antibacterial systems in atmosphere-connected water bodies.