Carbon-deposited TiO2 nanoparticle balls for high-performance visible photocatalysis

Abstract

Carbon-deposited TiO₂ nanoparticle-assembled submicrometer spheres, i.e., nanoparticle balls (NP balls), were fabricated with a uniform size by using a cone-jet electrospray; high-temperature pyrolysis of phenol-formaldehyde resol was then applied to achieve carbon deposition. The deposition of carbon during the pyrolysis stabilizes the anatase phase of TiO₂, and results in the preservation of the porous structure of the NP balls. The amount of deposited carbon can be controlled by varying the concentration of the resol solution coated on the NP balls. Carbon deposition results in the formation of a carbon layer on the TiO₂ surfaces as well as in the doping of the TiO₂ phase, which enable high visible light absorption. The adsorption capacity of the carbon-deposited NP balls is 20 times higher than that of bare NP balls. The carbon-deposited NP balls were tested in the photocatalytic decomposition of methylene blue. The carbon-deposited NP balls exhibited a decomposition rate of 0.02 mol h⁻¹ g⁻¹, which is the highest rate when compared to previous results measured under similar experimental conditions. Our approach provides a facile method for the fabrication of porous carbon-doped TiO₂ particles that are highly adsorptive and active visible light photocatalysts.