La-doped MIL-88B(Fe)-NH2: a mixed-metal-organic framework photocatalyst for highly efficient reduction of Cr(vi) in an aqueous solution

Minh Hue Dang Thi; Linh Giang Hoang Thi; Chinh Dang Huynh; Hoai Phuong Nguyen Thi; Duc D La

doi:10.1039/d4ra03351e

La-doped MIL-88B(Fe)-NH₂: a mixed-metal-organic framework photocatalyst for highly efficient reduction of Cr(vi) in an aqueous solution

RSC Adv. 2024 Jun 27;14(29):20543-20552. doi: 10.1039/d4ra03351e.

Authors

Minh Hue Dang Thi¹, Linh Giang Hoang Thi¹, Chinh Dang Huynh¹, Hoai Phuong Nguyen Thi², Duc D La^{3

4}

Affiliations

¹ School of Chemistry and Life Sciences, Hanoi University of Science and Technology Hanoi Vietnam.
² Department of Chemistry and Environment, Joint Vietnam-Russia Tropical Science and Technology Research Center 63 Nguyen Văn Huyen Street, Cau Giay Ha Noi Vietnam.
³ Laboratory of Advanced Materials Chemistry, Institute for Advanced Study in Technology, Ton Duc Thang University Ho Chi Minh City Vietnam [email protected].
⁴ Faculty of Applied Sciences, Ton Duc Thang University Ho Chi Minh City Vietnam.

Abstract

With the aim to resolve the problem of water pollution, we herein propose a new photocatalyst based on metal-organic frameworks (MOFs), called La-doped MIL-88B(Fe)-NH₂ (MIL-88B((1 - x)Fe/xLa)-NH₂), which was designed and employed for the photocatalytic reduction of Cr(vi) in aqueous solutions. MIL-88B((1-x)Fe/xLa)-NH₂ materials with different x values were synthesized via a one-pot solvothermal method. Their characteristics were investigated using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Brunauer-Emmett-Teller (BET) analysis, Fourier-transform infrared (FT-IR) spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). We found that compared to pristine MIL-88B(Fe)-NH₂ with a photocatalytic efficiency of 67.08, MIL-88B((1 - x)Fe/xLa)-NH₂ materials with x = 0.010, 0.025 and 0.050 exhibit excellent photocatalytic efficiencies reaching 88.21, 81.19 and 80.26%, respectively, after only 30 minutes of irradiation at a small catalyst dosage of 0.2 g L^-1. These La-doped MIL-88B(Fe)-NH₂ photocatalysts can work well under mild conditions (pH = 6). Furthermore, they are robust-can be recycled for at least four consecutive runs without any activity loss. This novel material is promising for the photocatalytic degradation of pollutants.