Bidentate carboxylate linked TiO2 with NH2-MIL-101(Fe) photocatalyst: a conjugation effect platform for high photocatalytic activity under visible light irradiation

Interfacial conjugation was employed to engineering preparation of TiO2@NH2-MIL-101(Fe) heterojunction photocataysts through carboxylate bidentate linkage with TiO2 and NH2-MIL-101(Fe), which can enhance the electron transfer capability from metal-organic frameworks (MOFs) to TiO2 and photocatalytic activity. The carbon nanospheres derived from glucose act as reducing agent and template to synthesize oxygen vacancies TiO2 hollow nanospheres. Then, the oxygen vacancies were employed as antennas to connect 2-aminoterephtalic acid as bidentate carboxylate chelating linkage on TiO2, which have been proved by the density functional theory (DFT) calculations. Subsequently, NH2MIL-101(Fe) was coordinatingly formed on the surface of TiO2. The conjugation effects between TiO2 and NH2-MIL101(Fe) enhanced the electron transfer capability and could also induce the band tail states to narrow bandgap of the composites. Thus, the photodegradability of methylene blue was remarkably enhanced under visible light irradiation. The degradation rate of TiO2@17%NH2-MIL-101(Fe) was 0.131 min 1, which was about 3.5 and 65 times higher than that of NH2-MIL-101(Fe) and TiO2, respectively. (C) 2020 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.