Enhanced photocatalytic degradation of methyl orange by TiO2/biochar composites under simulated sunlight irradiation

To solve the environmental problems caused by organic pollutants, in this work, the corn straw biochar (BC) was prepared by high-temperature pyrolysis, and a series of titanium dioxide/biochar composites (TiO2/BC) were prepared by ultrasonic assisted vacuum impregnation. Compared with pure TiO2, TiO2/BC(650) composite had good crystal structure, and larger specific surface area. Because of the improvement of its physical and chemical properties, the band edge absorption had certain red-shifted, and it had good light absorption properties. Furthermore, the results of photoluminescence spectroscopy (PL), transient photocurrent and electrochemical impedance showed that the lifetime of photogenerated charge in the TiO2/BC(650) composite was prolonged, which inhibited the recombination of photogenerated electron-hole pairs. Meanwhile, the photocatalytic degradation performance of TiO2/BC composites was evaluated using MO simulated pollutant under simulated sunlight irradiation. The results showed that the photocatalytic activity of TiO2/BC(T) (T = 400, 500, 600, 650, and 700 degrees C) prepared at different calcination temperatures were higher than that of pure TiO2, and TiO2/BC (650) exhibited the highest photocatalytic activity, and the degradation performance of 50 mg/L MO was 97.98%. Therefore, TiO2/BC composites are an environmental protection material capable of photocatalytic removal of organic pollutants.