Metallic Ti3O5 hierarchical porous microspheres with an enhanced photothermal property

γ-Ti3O5 is one kind of prominent non-stoichiometric metal oxide due to its intriguing ability in electric and electrochemical behaviors. This work reports another attractive property of γ-Ti3O5 hierarchical porous microspheres, the extremely effective photothermal property with a high photothermal conversion efficiency. Theory and experimental results indicate that γ-Ti3O5 hierarchical porous microspheres possess metallic features and display very strong localized surface plasma resonance effects over the visible and near-infrared region. Under simulated sunlight or near infrared light, the metallic γ-Ti3O5 exhibits a photothermal conversion efficiency of up to 65.29%. Under irradiation by a near-infrared laser with a wavelength of 808 nm, the γ-Ti3O5 hierarchical porous microspheres can significantly inhibit cancer cell viability in vitro and disrupt tumor tissue growth in vivo in a short period. In vitro and in vivo toxicity experiments demonstrate that it has good biocompatibility. The ultrahigh photothermal conversion efficiency and biocompatibility make the γ-Ti3O5 very attractive for technological uses in photothermal therapy, solar energy utilization, and infrared light detection and so on.