title: Turning Redundant Ligands into Treasure: A New Strategy for Constructing MIL-53(Al)@Nanoscale TiO2 Layers.
abstract: A strategy for in situ fabrication of nanoscale-thin layers of anatase TiO2 coated on the metal-organic framework (MOF) material, MIL-53(Al), is developed. The preparation conditions for crystallized TiO2 are normally incompatible with the thermal and chemical stability of MOFs. Based on our strategy, we found that the redundant organic ligands (1,4-benzenedicarboxylic acid, H2 BDC) within the pores of the as-synthesized MOF play a key function in the protection and support of the framework during hydrothermal loading of the TiO2 precursor, as well as in preventing the infiltration of the precursor into the pores. After annealing, a nanoscale-thin layer of highly crystalline anatase TiO2 , with a thickness of 6-10 nm, was successfully attached to the external surface of the MIL-53(Al) crystals, while the porous framework remains intact. The core-shell structure of the MOF@TiO2 nanocomposite endows the resulting materials with additional optical response and enhanced moisture and chemical stability.
authors.affiliation: College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092 Shanghai (P.R. China).
authors.forename: Yifan
authors.initials: Y
authors.lastname: Gu
authors.affiliation: College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092 Shanghai (P.R. China).
authors.forename: Yi-Nan
authors.initials: YN
authors.lastname: Wu
authors.affiliation: College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092 Shanghai (P.R. China).
authors.forename: Jingyi
authors.initials: J
authors.lastname: Shen
authors.affiliation: College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092 Shanghai (P.R. China).
authors.forename: Zehua
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092 Shanghai (P.R. China).
authors.forename: Shuyi
authors.initials: S
authors.lastname: Chen
authors.affiliation: College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092 Shanghai (P.R. China).
authors.forename: Huigong
authors.initials: H
authors.lastname: Lu
authors.affiliation: College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092 Shanghai (P.R. China). fengting@tongji.edu.cn.
authors.forename: Fengting
authors.initials: F
authors.lastname: Li
keywords: core-shell structures; enhanced stability; metal-organic frameworks; nanoscale coating; redundant ligands