title: Facile synthesis of amino-functionalized titanium metal-organic frameworks and their superior visible-light photocatalytic activity for Cr(VI) reduction.
abstract: Porous metal-organic frameworks (MOFs) have been arousing a great interest in exploring the application of MOFs as photocatalyst in environment remediation. In this work, two different MOFs, Ti-benzenedicarboxylate (MIL-125(Ti)) and amino-functionalized Ti-benzenedicarboxylate (NH2-MIL-125(Ti)) were successfully synthesized via a facile solvothermal method. The MIL-125(Ti) and NH2-MIL-125(Ti) were well characterized by XRD, SEM, XPS, N2 adsorption-desorption measurements, thermogravimetric analysis and UV-vis diffuse reflectance spectra (DRS). It is revealed that the NH2-MIL-125(Ti) has well crystalline lattice, large surface area and mesoporous structure, chemical and thermal stability, and enhanced visible-light absorption up to 520 nm, which was associated with the chromophore (amino group) in the organic linker. Compared with MIL-125(Ti), NH2-MIL-125(Ti) exhibited more efficient photocatalytic activity for Cr(VI) reduction from aqueous solution under visible-light irradiation. The addition of hole scavenger, the hole scavenger concentration and the pH value of the reaction solution played important roles in the photo-catalytic reduction of Cr(VI). The presence of Ti(3+)-Ti(4+) intervalence electron transfer was the main reason for photo-excited electrons transportation from titanium-oxo clusters to Cr(VI), facilitating the Cr(VI) reduction under the acid condition. It was demonstrated that amino-functionalized Ti(IV)-based MOFs could be promising visible-light photocatalysts for the treatment of Cr(VI)-contained wastewater.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
authors.forename: Hou
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China. Electronic address: yxz@hnu.edu.cn.
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Yuan
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.affiliation: School of Business, Central South University, Changsha 410083, PR China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
authors.forename: Lijian
authors.initials: L
authors.lastname: Leng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Wu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
authors.forename: Longbo
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Institute of Bio-energy, Hunan Academy of Forestry, Changsha 410004, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
mesh_terms: D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D008027:Light; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D016062:Porosity; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D000588:Amines; D009942:Organometallic Compounds; D002857:Chromium; C074702:chromium hexavalent ion; D014025:Titanium
keywords: Cr(VI); Ethanol; Metal-organic framework; Photocatalytic reduction; Titanium