Self-assembled highly crystalline TiO2 mesostructures for sunlight-driven, pH-responsive photodegradation of dyes

The development of new strategies and photocatalytic materials for practical environmental solutions remains a great challenge, particularly due to the large energy demands associated with various remediation processes. In this paper, we report the fabrication of self-assembled ordered mesoporous TiO2 with highly crystalline anatase structures as well as high surface area, and characterize their photocatalytic performance on the degradation of three typical dyes, including anionic methyl orange, cationic methylene blue, and neutral rhodamine B driven merely by sunlight. The results show that the dye photodegradation strongly depends on the charging state of both mesoporous TiO2 surface and dyes, which can be adjusted by the pH value of the solutions. Such charge-dependent photocatalytic functionality of mesoporous TiO2 can thus be exploited for highly efficient and selective dye photodegradation.