Visualizing the Interfacial Charge Transfer between Photoactive Microcystis aeruginosa and Hydrogenated TiO2

Exploring photoactive biotic–abiotic conjugations is of great importance for a variety of applications, but it remains difficult to probe the interfacial transfer of photoinduced charge carriers. In this work, Kelvin probe force microscopy, together with fluorescence imaging technique, were used to visually observe the spatial distribution and interfacial behavior of photocarriers in Microcystis aeruginosa/TiO2 hybrids. Experimental investigations suggested that photosynthetic microalgae cells were prone to trap photoholes from TiO2 photocatalysts. Oxygen vacancy defects in semiconductor exhibited significant impact on the charge migration, as the surface photovoltage of hydrogenated TiO2/microalgae hybrid was much higher than the pristine system. Profiting from the bioenhanced charge separation, biotic–abiotic architecture presented remarkably increased activity for photocatalytic inactivation of microalgae microorganisms. This work not only highlights the visual techniques for understanding the charge transfer around biotic–abiotic interface, but also provides a bioenhanced conjugation for the photocatalytic elimination of microorganisms in water treatment applications.