Highly efficient photothermal sterilization of water mediated by Prussian blue nanocages

Developing green and efficient techniques for water sterilization is of great importance to public health. In this work, highly efficient photothermal water sterilization mediated by Prussian blue nanocages (PBNs) has been realized. The PBNs are synthesized via a facile hydrothermal method, which can act as high-performance photothermal agents owing to their strong and broad optical absorption covering the entire ultraviolet, visible and near-infrared (NIR) regions as well as their competent photothermal conversion capability. Using Escherichia coli as the bacterial model, a high photothermal antibacterial efficacy (∼100%) is achieved upon NIR irradiation as short as 5 min even at a low dosage (100 μg mL−1). Moreover, the results of the sterilization of polluted drinking water with all kinds of mixed bacteria show that the PBNs can eliminate almost all bacteria upon 10 min of NIR irradiation. Importantly, the photothermal sterilization effect of the PBNs upon mild solar irradiation (0.1 W cm−2) is also demonstrated, showing a killing rate of ∼99% upon 10 min of irradiation. Our work has highlighted the great potential of photothermal sterilization employing solar light for practical water treatments.