Zr-Based Metal–Organic Framework (UiO-66) Doped with Rare-Earth Element (La, Y)-Supported Polyoxometalate Liquid for Oxidative Desulfurization of Dibenzothiophene Oxidation
Mingyu Liao, Yuanjie Xiao, Xiaolin Pi, Linfeng Zhang, Miaomiao Zheng, Jianbin Liu, Huadong Wu, Jia Guo
Abstract
By designing metal–organic frameworks (MOFs) doped with rare-earth elements, we can enhance catalytic activity and stability in a novel way. In the realm of oxidative desulfurization (ODS), polyoxometalate-ionic liquids have outstanding desulfurization performance. Herein, to create La-UiO-66 and Y-UiO-66, respectively, rare-earth elements (REs) of yttrium (Y) and lanthanum (La) were doped into the Zr-based metal–organic framework UiO-66. After that, the catalyst [C 12 mim] 3 PW 12 O 40 /RE-UiO-66 was prepared by supporting a type of polyoxometalate-ionic liquid [C 12 mim] 3 PW 12 O 40 with a large specific surface area and stable structure on RE-UiO-66 (RE = La or Y). The catalyst was characterized and analyzed by XRD, FT-IR, SEM, and other methods. The ODS reaction of the dibenzothiophene model oil was conducted in the oxidative desulfurization experiment with H 2 O 2 as the oxidant and [C 12 mim] 3 PW 12 O 40 /RE-UiO-66 as the catalyst, and the ideal reaction conditions were determined. Under the optimum reaction conditions ( T = 60 °C, O/S = 5), due to the strength of electron transfer over the catalysts, the DBT removal efficiencies of [C 12 mim] 3 PW 12 O 40 /0.18La-UiO-66–25% and [C 12 mim] 3 PW 12 O 40 /0.09Y-UiO-66–25% were 100% in 40 min and 97% in 60 min, respectively. The desulfurization efficiency was maintained at 91% after 13 cycles with [C 12 mim] 3 PW 12 O 40 /0.18La-UiO-66–25% as a catalyst. In addition, a proposed reaction mechanism for the ODS reaction over this catalyst was presented.