Design of single‐site catalysts with catalytic sites at atomic‐scale and high atom utilization, provides new opportunities to gain superior catalytic performance for targeted reactions. In this contribution, we report a one‐pot green approach for in situ implanting of single tungsten sites (up to 12.7 wt.%) onto the nodes of defective UiO‐66(Zr) structure via forming Zr‐O‐W bonds under solvent‐free condition. The catalysts displayed extraordinary activity for the oxidative removal of sulfur compounds (1000 ppm S) at room temperature within 30 min. The turnover frequency (TOF) value can reach 44.0 h−1 at 30 °C, which is 109.0, 12.3 and 1.2 times higher than that of pristine UiO‐66(Zr), WO3, and WCl6 (homogeneous catalyst). Theoretical and experimental studies show that the anchored W sites can react with oxidant readily and generate WVI‐peroxo intermediates that determine the reaction activity. Our work not only manifests the application of SSCs in the field of desulfurization of fuel oil but also opens a new solvent‐free avenue for fabricating MOFs based SSCs.

Nitro- and amino-functionalized UiO-66(Zr) have great potential in some applications.

Oxidative desulfurization is considered to be one of the most promising methods for producing ultra-low-sulfur fuels because it can effectively remove refractory sulfur-containing aromatic compounds under mild conditions. In this work, the oxidative desulfurization performance over UiO-66(Zr) is greatly enhanced by Ti ion exchange. This strategy is not only efficient for UiO-66(Zr) with crystal defects but also for UiO-66(Zr) with high crystallinity. In particular, the performance of UiO-66(Zr) with high crystallinity in the oxidative desulfurization of dibenzothiophene can be improved more than 11-fold, which can be mainly attributed to the introduction of active Ti sites.

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Creation of rich open metal sites (defect) on the nodes of metal−organic frameworks (MOFs) is an efficient approach to enhance their catalytic performance in heterogeneous reactions; however, direct generation of such defects remains challenging. In this contribution, we developed an in situ green route for rapid fabrication of defective MOF-808(Zr) with rich Zr-OH/OH 2 sites (occupying 25% Zr coordination sites) and hierarchical porosity without the assistance of formic acid and solvent. The optimal MOF-808(Zr) not only displayed superior activity in oxidative desulfurization (ODS) for removing 1000 ppm sulfur at ambient temperature within 20 min but also could convert 3.8 mmol of benzaldehyde to (dimethoxymethyl)benzene within 90 s at 30 °C. The turnover frequencies reached 45.4 h −1 for ODS and 3451 h −1 for acetalization, outperforming the most reported MOFbased catalysts. Theoretical calculation and experimental results show that the formed Zr-OH/OH 2 can react with H 2 O 2 to generate peroxo-zirconium species, which readily oxidize the sulfur compound. Our work provides a new approach to the synthesis of defectrich MOF-808(Zr) with the accessibility of active sites for target reactions.

Stable platforms of host–guest catalysts are indispensable in the field of heterogeneous catalysis, however, clarifying the specific effect of host remains challenging. Herein, polyoxometalate (POM) is encapsulated in three types of UiO‐66(Zr) with different controlled densities of defects by the aperture opening and closing strategy at ambient‐temperature. It is found that catalytic activity of POM for oxidative desulfurization (ODS) at room temperature is turned on when encapsulated in the defective UiO‐66(Zr), and the sulfur oxidation efficiency shows an obvious increasing trend (from 0.34 to 10.43 mmol g−1 h−1) with the increased concentration of defects in UiO‐66(Zr) host. The as‐prepared catalyst with the most defective host displays ultrahigh performance which removed 1000 ppm sulfur with exceptionally diluted oxidant at room‐temperature within 25 min. The turnover frequency can reach 620.0 h−1 at 30 °C, which surpassed all the reported MOFs based ODS catalysts. A substantial guest/host synergistic effect mediated by the defective sites in UiO‐66(Zr) is responsible for the enhancement. Density functional theory calculations reveal that OH/OH2 capped on the open Zr sites of host UiO‐66(Zr) can decompose H2O2 to OOH group and enables the formation of WVI‐peroxo intermediates that determine the ODS activity.

Functionalized metal-organic frameworks (MOFs) have drawn great attention for a wide range of applications. The development of functionalized MOFs with plentiful open metal sites (defects) provides an avenue for targeted...