Metal Organic Framework MIL-101 Research Articles

Efficient capture and storage of ammonia in robust aluminium-based metal-organic frameworks

The development of stable sorbent materials to deliver reversible adsorption of ammonia (NH3) is a challenging task. Here, we report the efficient capture and storage of NH3 in a series of robust microporous aluminium-based metal-organic framework materials, namely MIL-160, CAU-10-H, Al-fum, and MIL-53(Al). In particular, MIL-160 shows high uptakes of NH3 of 4.8 and 12.8 mmol g−1 at both low and high pressure (0.001 and 1.0 bar, respectively) at 298 K. The combination of in situ neutron powder diffraction, synchrotron infrared micro-spectroscopy and solid-state nuclear magnetic resonance spectroscopy reveals the preferred adsorption domains of NH3 molecules in MIL-160, with H/D site-exchange between the host and guest and an unusual distortion of the local structure of [AlO6] moieties being observed. Dynamic breakthrough experiments confirm the excellent ability of MIL-160 to capture of NH3 with a dynamic uptake of 4.2 mmol g−1 at 1000 ppm. The combination of high porosity, pore aperture size and multiple binding sites promotes the significant binding affinity and capacity for NH3, which makes it a promising candidate for practical applications.

Enhanced Solid-State Fluorescence of Flavin Derivatives by Incorporation in the Metal-Organic Frameworks MIL-53(Al) and MOF-5.

The flavin derivatives 10-methyl-isoalloxazine (MIA) and 6-fluoro-10-methyl-isoalloxazine (6F-MIA) were incorporated in two alternative metal-organic frameworks, (MOFs) MIL-53(Al) and MOF-5. We used a post-synthetic, diffusion-based incorporation into microcrystalline MIL-53 powders with one-dimensional (1D) pores and an in-situ approach during the synthesis of MOF-5 with its 3D channel network. The maximum amount of flavin dye incorporation is 3.9 wt% for MIA@MIL-53(Al) and 1.5 wt% for 6F-MIA@MIL-53(Al), 0.85 wt% for MIA@MOF-5 and 5.2 wt% for 6F-MIA@MOF-5. For the high incorporation yields the probability to have more than one dye molecule in a pore volume is significant. As compared to the flavins in solution, the fluorescence spectrum of these flavin@MOF composites is broadened at the bathocromic side especially for MIA. Time-resolved spectroscopy showed that multi-exponential fluorescence lifetimes were needed to describe the decays. The fluorescence-weighted lifetime of flavin@MOF of 4 ± 1 ns also corresponds to those in solution but is significantly prolonged compared to the solid flavin dyes with less than 1 ns, thereby confirming the concept of "solid solutions" for dye@MOF composites. The fluorescence quantum yield (ΦF) of the flavin@MOF composites is about half of the solution but is significantly higher compared to the solid flavin dyes. Both the fluorescence lifetime and quantum yield of flavin@MOF decrease with the flavin loading in MIL-53 due to the formation of various J-aggregates. Theoretical calculations using plane-wave and QM/MM methods are in good correspondence with the experimental results and explain the electronic structures as well as the photophysical properties of crystalline MIA and the flavin@MOF composites. In the solid flavins, π-stacking interactions of the molecules lead to a charge transfer state with low oscillator strength resulting in aggregation-caused quenching (ACQ) with low lifetimes and quantum yields. In the MOF pores, single flavin molecules represent a major population and the computed MIA@MOF structures do not find π-stacking interactions with the pore walls but only weak van-der-Waals contacts which reasons the enhanced fluorescence lifetime and quantum yield of the flavins in the composites compared to their neat solid state. To analyze the orientation of flavins in MOFs, we measured fluorescence anisotropy images of single flavin@MOF-5 crystals and a static ensemble flavin@MIL53 microcrystals, respectively. Based on image information, anisotropy distributions and overall curve of the time-resolved anisotropy curves combined with theoretical calculations, we can prove that all fluorescent flavins species have a defined and rather homogeneous orientation in the MOF framework. In MIL-53, the transition dipole moments of flavins are orientated along the 1D channel axis, whereas in MOF-5 we resolved an average orientation that is tilted with respect to the cubic crystal lattice. Notably, the more hydrophobic 6F-MIA exhibits a higher degree order than MIA. The flexible MOF MIL-53(Al) was optimized essentially to the experimental large-pore form in the guest-free state with QuantumEspresso (QE) and with MIA molecules in the pores the structure contracted to close to the experimental narrow-pore form which was also confirmed by PXRD. In summary, the incorporation of flavins in MOFs yields solid-state materials with enhanced rigidity, stabilized conformation, defined orientation and reduced aggregations of the flavins, leading to increased fluorescence lifetime and quantum yield as controllable photo-luminescent and photo-physical properties.

Breathing Behaviour Modification of Gallium MIL-53 Metal-Organic Frameworks Induced by the Bridging Framework Inorganic Anion.

Controlling aspects of the μ2 -X- bridging anion in the metal-organic framework Ga-MIL-53 [GaX(bdc)] (X- =(OH)- or F- , bdc=1, 4-benzenedicarboxylate) is shown to direct the temperature at which thermally induced breathing transitions of this framework occur. In situ single crystal X-ray diffraction studies reveal that substituting 20 % of (OH)- in [Ga(OH)(bdc)] (1) for F- to produce [Ga(OH)0.8 F0.2 (bdc)] (2) stabilises the large pore (lp) form relative to the narrow pore (np) form, causing a well-defined decrease in the onset of the lp to np transition at higher temperatures, and the adsorption/desorption of nitrogen at lower temperatures through np to lp to intermediate (int) pore transitions. These in situ diffraction studies have also yielded a more plausible crystal structure of the int-[GaX(bdc)] ⋅ H2 O phases and shown that increasing the heating rate to a flash heating regime can enable the int-[GaX(bdc)] ⋅ H2 O to lp-[GaX(bdc)] transition to occur at a lower temperature than np-[GaX(bdc)] via an unreported pathway.

A LDH Template Triggers the Formation of a Highly Compact MIL-53 Metal-Organic Framework Membrane for Acid Upgrading.

Highly compact metal-organic framework (MOF) membranes offer hope for the ambition to cope with challenging separation scenarios with industrial implications. A continuous layer of layered double hydroxide (LDH) nanoflakes on an alumina support as a template triggered a chemical self-conversion to a MIL-53 membrane, with approximately 8 hexagonal lattices (LDH) traded for 1 orthorhombic lattice (MIL-53). With the sacrifice of the template, the availability of Al nutrients from the alumina support was dynamically regulated, which resulted in synergy for producing membranes with highly compact architecture. The membrane can realize nearly complete dewatering from formic acid and acetic acid solutions, respectively, and maintain stability in a continuous pervaporation over 200 h. This is the first success in directly applying a pure MOF membrane to such a corrosive chemical environment (lowest pH value of 0.81). The energy consumption is saved by up to 77 % when compared with the traditional distillation.

Preparation of heterogeneous catalysts by the post-synthetic modification of mesoporous metal-organic framework MIL-101

Preparation of heterogeneous catalysts by the post-synthetic modification of mesoporous metal-organic framework MIL-101

Constructing Defective Heterojunctions of BiOBr Nanosheets and Hollow NH2 -functionalized MOFs for Visible-light-driven CO2 Reduction with Nearly 100% CO Selectivity by Pure H2 O.

To rationally design photocatalysts with high generation rate and selectivity of target product remains an ongoing challenge for CO2 conversion in pure H2 O. Herein, from the viewpoint of enhancing the separation efficiency of photoinduced electron-hole pairs and the adsorption ability of CO2 molecule, we have constructed a series of Z-scheme defective heterojunctions of BiOBr nanosheets and hollow NH2 -functionalized metal-organic framework (MOF) MIL-125 with Ti ions as metal centers (noted as NH2 -MIL-125(Ti)). Systematic characterization demonstrates that the BiOBr nanosheets are anchored on the surface of hollow NH2 -MIL-125(Ti), which facilitates the efficient visible-light-driven catalytic reduction of CO2 to CO with nearly 100% selectivity by pure H2 O. Especially, the CO generation rate of optimized catalyst with oxygen vacancies reaches 459.7 μmol g-1 h-1 , which is higher than those of all the previously reported photocatalysts without sacrificial reagents. This approach provides a new insight for using inorganic semiconductors to fabricate semiconducting MOFs for high-efficiency photocatalytic reduction CO2 into value-added chemicals by pure H2 O.

Isolation of Cytochrome C for Proteomics with Lindqvist-type Polyiodate Modified Metal Organic Framework

Separation and purification of Cytochrome C (Cyt-C) is important for proteomic. High efficient and selective pretreatment method for Cyt-C in real samples are always needed. Herein, polyniobate (K7H[Nb6O19]·13H2O, Nb6O19) is modified on a metal-organic framework MIL-125(Ti) through intermolecular hydrogen bonds and an aqueous-stable composite Nb6O19/MIL-125(Ti) is successfully prepared to pretreat complex protein sample. Protein adsorption studies have shown that Nb6O19/MIL-125(Ti) can promote the selective adsorption of Cyt-C due to the synergistic effect of electrostatic and hydrogen-bond interactions. At pH=10.0 (Britton-Robinson buffer), the adsorption efficiency of 300 μL 100 μg·mL−1 Cyt-C onto 1.0 mg Nb6O19/MIL-125(Ti) can reach 99.5%. The adsorption behavior of Cyt-C fits well with the Langmuir adsorption model, corresponding to a maximum theoretical adsorption capacity of 168.35 mg·g−1. Using 3 mol·L−1 NaCl as the eluent, a high elution efficiency of 92.19% is obtained. In addition, the results of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis confirm that Nb6O19/MIL-125(Ti) efficiently adsorbed Cyt-C from scrofa heart extraction. LC-MS/MS spectrometry results show that the purification of Cyt-C reduces the abundance from the 12th to the 154th place after Nb6O19/MIL-125(Ti) treatment. Moreover, low abundant proteins, e.g., Superoxide dismutase 1, IF rod domain-containing protein and Ubiquitin-60S ribosomal protein L40 were considerably enriched. These outcomes confirm the practicability of Nb6O19/MIL-125 (Ti) as a Cyt-C extractant has potential application value in scrofa heart proteomics.

Synthesis, characterization and ethylene oligomerization of MIL-125(Ti)-NH2 grafted salicylaldehyde nickel complexes

Metal-organic framework MIL-125(Ti)-NH2 was prepared and coordinated with salicylaldehyde and NiCl2·6H2O to create a heterogeneous catalyst for ethylene polymerization. The structure of the products was characterized by a variety of physical methods, such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma mass spectrometry (ICP-MS), and nitrogen adsorption-desorption. The catalytic performance of MIL-125(Ti)-NH2-Sal-Ni was also investigated. The results showed that the reaction temperature, Al/Ni molar ratio, and ethylene pressure influenced on the catalytic activity and product selectivity. Under optimal reaction conditions, the catalytic activity of MIL-125(Ti)-NH2-Sal-Ni for ethylene oligomerization could reach 5.90 × 104 g·(mol Ni·h)−1 using cyclohexane as the solvent and MAO as the co-catalyst; the main products were C4 and C6. In addition, MIL-125(Ti)-NH2-Sal-Ni had good catalytic stability and recycling, which could be reused at least twice without significant loss of activity. Moreover, based on the evaluation of catalytic performance, the catalytic ethylene oligomerization mechanism of MIL-125(Ti)-NH2-Sal-Ni was also deduced.

Catalytic performance and kinetic modeling of n-hexane isomerization over phosphomolybdic acid (HPMo) combining palladium and platinum supported on metal-organic framework MIL-101(HPW)

A metal-organic framework MIL-101(HPW) was synthesized by hydrothermal reaction, and phosphomolybdic acid (HPMo) was synthesized by its precursor solution. Then (Pd + Pt)/HPMo/MIL-101(HPW) with different wt% were prepared by the impregnation method. The synthesized samples were characterized by XRD, FT-IR, NH3-TPD, N2 adsorption, FESEM, and TGA, and their performances were investigated in n-hexane isomerization. Under the optimized operating conditions (temperature of 180 °C, H2/nC6 molar ratio of 2, and WHSV of 3 h−1), the appropriate yield for the nC6 isomerization was provided. The (0.2%Pd + 0.3%Pt)/50%HPMo/MIL-101(HPW) sample showed a lifetime of 720 min with 92.5% iC6 selectivity and 75.3% nC6 conversion. Kinetic modeling of the n-hexane isomerization reaction was also performed, in which the classical bifunctional mechanism was used to calculate the kinetic parameters. The validity of the bifunctional behavior was proved by the high value of the statistical correlation coefficient of this model. The apparent activation energy of this mechanism was calculated at 42.5 kJ mol−1.

In-situ synthesis of Fe7S8 on metal sites of MOFs as high-capacity and fast-kinetics anodes for sodium ion batteries

Low cost and high theoretical capacity are the main directions for the development of anode materials for sodium-ion batteries in the future, while iron sulfide fits in with this expectation. In this paper, nano-size porous Fe7S8 anode (Fe7S8 @MC) material with its Fe and mesoporous carbon (MC) derived from the metal-organic framework (MOF) MIL-53 (Fe) for the sodium ion battery is successfully prepared by hydrothermal reaction combined with carbonization and vulcanization process. The iron ion sites are fully utilized to form carbon coated Fe7S8 basic monomers, and the monomers are connected with the carbon skeleton to form a porous nanostructure, which can not only maintain high energy storage capacity, but also ensures the stability of the electrode structure, so as to obtain stable cycling and rate performance. At the current density of 500 mA g-1, the reversible specific capacity of the obtained material is still 413.9 mAh g-1, even after 100 cycles. In particular, the reversible capacity of 390.2 mAh g-1 can still be obtained at a high current density of 1 A g-1. Simultaneously, the obtained material can recover 97% of the initial capacity after being charged and discharged at the high specific current of 1 A g-1. The total sodium storage capacity is contributed by a combination of capacitance and diffusion. In addition, the calculated result for the apparent activation energy (Ea = 30.89 kJ mol-1), the diffusion apparent activation energy (EaD = 14.41 kJ mol-1), and the sodium ion diffusion coefficient (DNa+ = 2.55 × 10-12 cm2 s-1) show that the obtained materials have rapid reaction kinetics. Therefore, synthetic materials have excellent research potential and are expected to be used in high-performance sodium ion batteries with practical efficacy.

Spectroscopic and reactive characterization of mixed-metal Fe-Cr trimer nodes in metal-organic framework MIL-100.

Metal-organic framework MIL-100 is synthesized featuring heterometallic Fe and Cr M3O nodes where mixing of the metals within the nodes is evidenced using a combination of in situ IR spectroscopy, NO titrations, and CO oxidation kinetics. Reactivity data indicate distinctive properties of the bimetallic nodes.

Metal-organic framework based drug delivery systems as smart carriers for release of poorly soluble drugs hydrochlorothiazide and dapsone.

Drug delivery systems (DDSs) that are derived from biocompatible carriers are attractive platforms for sustained release of drugs. In particular, sustained and controlled release of poorly soluble BCS (Biopharmaceutics Classification System) class IV drugs is important and this requires the development of new DDSs. In this work, we exploit two porous metal-organic frameworks (MOFs) MIL-100(Fe) and MIL-53(Fe) as carriers/DDSs for the release of two BCS class IV drugs hydrochlorothiazide (HCT) and dapsone (DAP). The chosen MOFs are known to possess good physicochemical stability and we realized high drug loading capacity that is attributed to the high porosity of the MOFs. The drug-encapsulated MOFs were characterized thoroughly and our results show ∼23.1% loading of HCT in MIL-100(Fe) and ∼27.6% loading of DAP in MIL-Fe(53), respectively. The release study of these drugs was carried out under simulated physiological conditions that shows sustained release of the drug molecules from the MOFs up to 72 h. Cell viability studies through MTT assays show insignificant cytotoxicity signalling biocompatibility of the proposed DDSs. Our investigations suggest MIL-100(Fe) and MIL-53(Fe) are potential DDSs for enhancing the performance of poorly soluble drugs HCT and DAP.

Electrostatic assembly of gold nanoparticle and metal-organic framework nanoparticles attenuates amyloid β aggregate-mediated neurotoxicity.

The deposition of amyloid β (Aβ) is a conventional pathological hallmark of Alzheimer's disease (AD). Consequently, the inhibition of Aβ aggregation combined with the disaggregation of Aβ fibrils is an important therapeutic method for AD treatment. In this study, a gold nanoparticle-decorated porous metal organic framework MIL-101(Fe) (AuNPs@PEG@MIL-101) was created as an Aβ inhibitor. The high positively charged MIL-101 induced a high number of Aβ40 to be absorbed or aggregated on the surface of nanoparticles. In addition, AuNPs improved the surface property of MIL-101, causing it to uniformly bind Aβ monomers and Aβ fibrils. Thus, this framework can efficiently suppress extracellular Aβ monomer fibrillation and disrupt the preformed Aβ fibers. AuNPs@PEG@MIL-101 also decreases intracellular Aβ40 aggregation and the amount of Aβ40 immobilized on the cell membrane, thus protecting PC12 cells from Aβ40-induced microtubular defects and cell membrane damage. In summary, AuNPs@PEG@MIL-101 shows great potential for application in AD therapy.

Sulfur-modulated metal–organic framework MIL-101(Fe) with CQDs anchored as an efficient light-driven photocatalyst: photocatalytic performance and mechanism investigation

A novel sulfur-modulated metal–organic framework photocatalyst, MIL-101(Fe), with CQDs anchored on its surface has been successfully synthesized to efficiently separate photo-induced carriers for the degradation of Rhodamine B and Cr6+ removal.

Preparation of metal-organic framework from in situ self-sacrificial stainless-steel matrix for efficient water oxidation

The oxygen evolution reaction (OER) on the anode is one of the key half-cell reactions in water electrolysis and metal-air batteries, and its reaction process is mainly hampered by sluggish kinetics and low efficiency. In this work, a series of MIL-53 metal-organic framework (MOF) derived materials grown on self-sacrificial SSM substrate was designed and synthesized for efficient water oxidation in alkaline solutions. The as-obtained FeNiBDC/SSM (SSM = stainless steel matrix and H2BDC = benzene-1,4-dicarboxylic acid) with MIL-53 MOF of uniform morphology and high porosity was successfully synthesized via a facile one-step method using recycled stainless steel as a template. Afterward, FeNiBDC/SSM was accompanied by morphological and structural changes during the OER process while the modified MOF components on the SSM substrate degraded into Fe/NiOOH species, which serve as catalytic centers. After the stability test for 100 h, the used optimal FeNiBDC/SSM2 exhibited a promising electrocatalytic OER performance with a low Tafel slope of 74.5 mV dec-1, a small overpotential of 239 mV at 10 mA cm-2, and high current retention of 95.20 %. This work provides a new research idea for the sustainable recycling of existing resources and the one-step in-situ preparation of MOF/substrate electrocatalyst for OER.

MIL-101(CuFe) Nanozymes with Excellent Peroxidase-like Activity for Simple, Accurate, and Visual Naked-Eye Detection of SARS-CoV-2.

The COVID-19 pandemic has spread to every corner of the world and seriously affected our health and daily activities in the past three years; thereby, it is still urgent to develop various simple, quick, and accurate methods for early detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. Nanozymes, a kind of nanomaterial with intrinsic enzyme-mimicking activity, have emerged as a suitable alternative for both therapy and diagnosis of SARS-CoV-2. Here, ultrasensitive and ultrafast MIL-101(CuFe)-CD147 biosensors are established for the detection of SARS-CoV-2 by a simple colorimetric method. A MIL-101(CuFe) metal-organic framework has excellent peroxidase-like activity due to the synergistic effect of Fe and Cu atoms. In addition, the MIL-101(CuFe)-CD147 biosensor shows great potential to detect the various variants of SARS-CoV-2 due to the universal receptor of CD147. The enzyme-based biosensor for the detection of SARS-CoV-2 achieves a very low limit of detection (about 3 PFU/mL) within 30 min. Therefore, the present method provides a new generation of an alternative approach for highly sensitive and visual diagnosis of COVID-19.

Preparation of N and Ce Co-doped MIL-101(Fe) Heterogeneous Catalysts for Efficient Electro-Fenton Oxidation

Design and synthesis of high-efficiency and stable heterogeneous catalysts for the electro-Fenton process remain challenging. In this study, a co-doped Ce and N metal–organic framework MIL-101(Fe) heterogeneous catalyst (Ce/N-MIL-101(Fe) was synthesized by a facile one-step solvothermal method. Polyvinyl pyrrolidone played dual roles during the fabrication process, which not only acted as a nitrogen source for doping but also prevented MIL-101(Fe) molecules from aggregating and reinforcing the formation crystal with a complete polyhedral crystal shape. The introduction of Ce significantly enhanced the density of active sites and promoted the Fe3+/Fe2+ cycle of the reaction system. Owing to the specific structure and properties, the rate of electron transfer in the catalytic process was significantly promoted. The synthesized Ce/N-MIL-101(Fe) catalyst exhibited a high degradation rate for dyes (>98%) with competitive stability and reusability. Moreover, compared with common electro-Fenton catalysts usually operated in a limited pH range of 3.0–6.0, the working pH range of Ce/N-MIL-101(Fe) was widened up to 10.0. The design concept for producing abundant active sites with co-doping into frameworks can be extended to more heterogeneous electro-Fenton catalysts constituted by other porous materials.

Porous Li4Ti5O12-induced cathode electrolyte interphases enable sustainable single-crystalline NCM cathodes

The cathode electrolyte interphase (CEI) layer derived on the cathode surface has a great influence on the coulombic efficiency, energy efficiency, rate performance, self-discharge, and cycling life of the lithium-ion batteries (LIBs). For layered nickel-rich cathodes, the electrochemically-inert residual lithium (e.g., Li2CO3, LiHCO3) combined with the continuous growth of CEI under high voltage (≥4.5 V vs Li/Li+) further increases the difficulty of regulating the activity and stability of LIBs. In this work, single-crystalline LiNi0.5Co0.2Mn0.3O2 (NCM523) is modified with porous Li4Ti5O12 particles through a simple solid synthesis process between residual lithium and metal–organic framework MIL-125(Ti). Here, metal–organic frameworks (MOFs) play an important role to thoroughly derive porous Li4Ti5O12 with a decentralized but not fully covered situation on the NCM523 surface. Moreover, Ti4+-rich Li4−xTi5O12−y would arise when the Li+ and O2– are removed from Li4Ti5O12 under a high voltage, which can promote the growth of cathode electrolyte interphase (CEI) along with enhanced capacity and stability of the NCM523 single crystals. Based on the MOFs materials, a new method of modifying cathodes with promoted CEI film was designed, which could be a reference for the development of high voltage and nickel-rich cathodes.

Internalization of the Metal-Organic Framework MIL-101(Cr)-NH2 by a Freshwater Alga and Transfer to Zooplankton.

The common metal-organic framework (MOF) MIL-101(Cr)-NH2 has attracted considerable attention due to its great potential applications in the environmental field. Nevertheless, its behavior and fate in aquatic systems are unknown. This study quantified and visualized the interactions of MIL-101(Cr)-NH2 with the freshwater phytoplanktonic alga Chlamydomonas reinhardtii and its potential trophic transfer to zooplankton. The unicellular alga absorbed and accumulated the MOF by surface attachment, forming agglomerates and eventually cosettling out from water. Bioimaging revealed that MIL-101(Cr)-NH2 was internalized by the algal cells and mainly occurred in the pyrenoid. Without algae in a freshwater system, MIL-101(Cr)-NH2 was ingested by Daphnia magna, showing steadily increasing concentrations approaching 1-9% of dry body weight. Addition of algae substantially suppressed D. magna uptake of MIL-101(Cr)-NH2 by 63.8-97.9%. Such inhibition could be explained by the competitive uptake of MOF by the algae and the inductive effects of algal food on MOF elimination by D. magna. The MOF (≤1 mg/L) ingested by D. magna was centered in the gut regions, whereas large MOF or algae-MOF aggregates were adsorbed onto the carapace and appendages, including the antennae, at 10 mg/L. Overall, the algae were the major targets for MIL-101(Cr)-NH2, with nearly all algal cells settling out at 10 mg/L within 24 h. The possibility of trophic transfer of MIL-101(Cr)-NH2 to D. magna in aquatic systems with algae present was limited due to its low accumulation potential and short retention time in D. magna.

TiO2-In-MIL-101(Cr) with Visible Light-Induced Peroxidase Activity for Colorimetric Detection of Blood Glucose.

In this work, metal-organic framework MIL-101(Cr) with regular morphology, stable structure, and good dispersion was prepared by the hydrothermal method. MIL-101(Cr) has two different sizes of pores, but after TiO2 nanoparticles (NPs) were in situ prepared, the two pores disappear. The result demonstrates that TiO2 NPs were located in the pores of MIL-101(Cr). TiO2-decorated MIL-101(Cr) forms an inside type II heterojunction and the band gap energy is narrowed, which can promote electron-hole separation and enhance the light absorption. Therefore, the heterojunction shows a high visible light-induced peroxidase-like activity. Kinetic studies exhibit that the K m value of TiO2-in-MIL-101(Cr) to TMB is 0.17 mM, and the affinity of TiO2-in-MIL-101(Cr) is higher than that of natural horseradish peroxidase (HRP). Then, a "turn-on" colorimetric assay based on TiO2-in-MIL-101(Cr) was constructed for the detection of blood glucose. The detection range is 1-100 μM (R 2 = 0.9950) with a limit of detection (LOD) of 1.17 μM. Compared with the clinical method, the constructed colorimetric method has accurate and reliable results for the clinical detection. The anti-interference experiment confirms that the method has high selectivity to glucose.