TiO2/core-shell structured carbon support materials derived from hydrothermal carbonization of waste masks biomass: A green photocatalyst

• The surface area of the core-shell structured carbon was 87.20 m 2 g -1 . • MC-TiO 2 increased the light absorption capacity and extended the electron-hole pair recombination time. • MC-TiO 2 exhibited the highest photodegradation yield among all photocatalysts. • The waste masks problem, one of the negative effects of COVID-19, was turned into an advantage in this study. Surgical masks have become mandatory to protect against the COVID-19 epidemic. For this reason, the amount of waste masks has also reached severe dimensions. Turning these waste masks into functional materials (MC) in a green synthesis method is critical. In this study, carbon material from waste masks was synthesized by the hydrothermal carbonization method (HTC) and was used to increase the photocatalytic activity of TiO 2 . In addition, TiO 2 nanoparticles were successfully synthesized by the solvothermal method. Thermo-gravimetric analysis (TGA), scanning-electron microscope (SEM), X-ray diffraction (XRD), Fourier transform- infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), transmission-electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), electrochemical-impedance spectroscopy (EIS) and Brunauer–Emmett–Teller (BET) analyzes were performed to illuminate the photocatalytic properties of the MC-TiO 2 photocatalyst. In this sense, the functionality of the shell-core skeleton-based new generation carbon material was also investigated. The photocatalytic activity of the green type of photocatalyst was detected by comparing methylene blue (MB) and phenol photodegradation rates. In photocatalytic degradation experiments, both UV-A effect and visible light effect were examined. New type of photocatalyst an exhibited excellent photocatalytic effect. Superior photodegradation capacity may be referred as to the core-shell composition and functional groups of the effective carbon support material synthesized by the HTC method. In particular, the photocatalytic effect of the novel carbon support material is discussed in-depth with the proposed mechanism. With the present study, we aimed to bring a green perspective to the photocatalytic studies in the literature.