Robust photocatalytic benzene degradation using mesoporous disk-like N-TiO2 derived from MIL-125(Ti)

N-doped anatase-rutile titanium dioxide (N-TiO2) is a classical semiconductor widely used in environmental remediation. Its photocatalytic performance is typically affected by its morphology, porous structure, and phase composition. Herein, disk-like mesoporous N-TiO2 was prepared by calcining MIL-125(Ti) and melamine matrix at different temperatures in air. The photocatalytic efficiency of the prepared mesoporous N-TiO2 for the photo-oxidation of gaseous benzene under visible-light irradiation was studied. With respect to light absorption and mass transfer, as-prepared N-TiO2 annealed at 500 °C (MM-500) showed the best photocatalytic activity with corresponding photodegradation and mineralization efficiencies of 99.1% and 72.0%, respectively. In addition, MM-500 exhibited excellent reusability and stability in cyclic experiments, in which 84.8% of gaseous benzene could still be photodegraded after 10 experimental cycles. Furthermore, electron spin resonance analysis indicated that •OH and •O2− radicals were the dominating reactive oxygen species during the photo-oxidation process. Their excellent performance suggests that the as-prepared N-TiO2 photocatalysts can be used to eliminate volatile organic compounds.