Indium-based Metal-organic Framework Research Articles

Aggregation-induced electrochemiluminescence of an indium-based metal–organic framework and resonance energy transfer strategy for the sensitive detection of β2-microglobulin

This study aimed to construct a novel aggregation-induced electrochemiluminescence (AIECL) system with an indium-based metal–organic framework (In-MOF) as a new luminophore and K2S2O8 as a co-reactant. In the constructed electrochemiluminescence (ECL) system, In-MOF served not only as a novel luminophore but also as a co-reaction accelerator. The In-MOF produced strong cathodic ECL emission over the wavelength range of 425–600 nm. The aggregation-caused quenching effect was overcome by altering the π-π stacking structure of 9,10-di(p-carboxyphenyl)anthracene (DPA) aggregates through coordination with metal ions. The In-MOF exhibited efficient ECL performance and better stability than the DPA ligand. Then, a novel quenched sensor based on the quenching effect of CeO2@PDA on the In-MOF ECL emission was fabricated for detecting β2-microglobulin (β2M). The immunosensor demonstrated an excellent linear relationship with a wide linear range (10 fg/mL – 200 ng/mL) and a low detection limit (2.9 fg/mL, S/N = 3) under optimized experimental conditions. The proposed biosensor had high sensitivity, reasonable specificity, high stability, and reproducibility, thus positively affecting the clinical application of sensing analysis.

In2O3/Bi2O3 interface induces ultra-stable carbon dioxide electroreduction on heterogeneous InBiOx catalyst

The electrochemical reduction of CO2 (ERCO2) has emerged as one of the most promising methods for achieving both renewable energy storage and CO2 recovery. However, achieving both high selectivity and stability of catalysts remains a significant challenge. To address this challenge, this study investigated the selective synthesis of formate via ERCO2 at the interface of In2O3 and Bi2O3 in the InBiO6 composite material. Moreover, InBiO6 was synthesized using indium-based metal–organic frameworks as precursor, which underwent continuous processing through ion exchange and thermal reduction. The results revealed that the formate Faradaic efficiency (FEformate) of InBiO6 reached nearly 100 % at −0.86 V vs. reversible hydrogen electrode (RHE) and remained above 90 % after continuous 317-h electrolysis, which exceeded those of previously reported indium-based catalysts. Additionally, the InBiO6 composite material exhibited an FEformate exceeding 80 % across a wide potential range of 500 mV from −0.76 to −1.26 V vs. RHE. Density-functional theory analysis confirmed that the heterogeneous interface of InBiO6 played a role in achieving optimal free energies for *OCHO on its surface. Furthermore, the addition of Bi to the InBiO6 matrix facilitated electron transfer and altered the electronic structure of In2O3, thereby enhancing the adsorption, decomposition, and formate production of *OCHO.

In Situ Reconstruction of Scalable Amorphous Indium-Based Metal-Organic Framework for CO2 Electroreduction to Formate over an Ultrawide Potential Window.

Amorphous metal-organic frameworks (aMOFs) are highly attractive for electrocatalytic applications due to their exceptional conductivity and abundant defect sites, but harsh preparation conditions of "top-down" strategy have hindered their widespread use. Herein, the scalable production of aMIL-68(In)-NH2 was successfully achieved through a facile "bottom-up" strategy involving ligand competition with 2-methylimidazole. Multiple in situ and ex situ characterizations reveal that aMIL-68(In)-NH2 evolutes into In/In2O3-x as the genuine active sites during the CO2 electrocatalytic reduction (CO2RR) process. Moreover, the retained amino groups could enhance the CO2 adsorption. As expected, the reconstructed catalyst demonstrates high formate Faradaic efficiency values (>90%) over a wide potential range of 800 mV in a flow cell, surpassing most top-ranking electrocatalysts. Density functional theory calculations reveal that the abundant oxygen vacancies in aMIL-68(In)-NH2 induce more local charges around electroactive sites, thereby promoting the formation of HCOO* intermediates. Furthermore, 16 g of samples can be readily prepared in one batch and exhibit almost identical CO2RR performances. This work offers a feasible batch-scale strategy to design amorphous MOFs for the highly efficient electrolytic CO2RR.

CuO (111) Microcrystalline Evoked Indium-Organic Framework for Efficient Electroreduction of CO2 to Formate.

Electrochemical reduction of carbon dioxide (CO2RR) to formate is economically beneficial but suffers from poor selectivity and high overpotential. Herein, enriched microcrystalline copper oxide is introduced on the surface of indium-based metal-organic frameworks. Benefiting from the CuO (111) microcrystalline shell and formed catalytic active In-Cu interfaces, the obtained MIL-68(In)/CuO heterostructure display excellent CO2RR to formate with a Faradaic efficiency (FE) as high as 89.7% at low potential of only -0.7 V vs. RHE in a flow cell. Significantly, the membrane electrode assembly (MEA) cell based on MIL-68(In)/CuO exhibit a remarkable current density of 640.3mAcm-2 at 3.1V and can be stably operated for 180h at 2.7 V with a current density of 200mAcm-2. The ex/in situ electrochemical investigations reveal that the introduction of CuO increases the formation rate of the carbon dioxide reduction intermediate *HCOO- and inhibits the competitive hydrogen evolution reaction. This work not only provides an in-depth study of the mechanism of the CO2RR pathways on In/Cu composite catalyst but also offers an effective strategy for the interface design of electrocatalytic carbon dioxide reduction reaction.

Ligand-Functionalized MIL-68-type Indium(III) Metal-Organic Frameworks with Prominent Intrinsic Proton Conductivity.

Indium-based metal-organic frameworks (In-MOFs) have now become an attractive class of porous solids in materials science and electrochemistry due to their diverse structures and promising applications. In the field of proton conduction, to find more crystalline MOFs with splendid proton-conductive properties, herein, five three-dimensional isostructural In-MOFs, MIL-68-In or MIL-68-In-X (X = NH2, OH, Br, or NO2) using terephthalic acid (H2BDC) or functionalized terephthalic acids (H2BDC-X) as multifunctional linkages were efficiently fabricated. First, the outstanding structural stability of the five MOFs, including thermal and water stability, was verified by thermal analysis and powder X-ray diffraction. Subsequently, the H2O-mediated proton conductivities (σ) were fully assessed and compared. Notably, their σ evinced a significant positive correlation between the temperature or relative humidity (RH) and varied with the functional groups on the organic ligands. Impressively, their highest σ values are up to 10-3-10-4 S/cm (100 °C/98% RH) and change in this order: MIL-68-In-OH (1.72 × 10-3 S/cm) > MIL-68-In-NH2 (1.70 × 10-3 S/cm) > MIL-68-In-NO2 (4.47 × 10-4 S/cm) > MIL-68-In-Br (4.11 × 10-4 S/cm) > MIL-68-In (2.37 × 10-4 S/cm). Finally, the computed activation energy values under 98 or 68% RHs are assessed, and the related proton conduction mechanisms are speculated. Moreover, after electrochemical testing, these MOFs illustrate remarkable structural rigidity, laying a meritorious material foundation for future applications.

Bimetal-regulated indium-based metal-organic framework family realizing highly efficient photo/electrocatalytic hydrogen evolution reaction

Based on promptly emerging global necessity and future environmental considerations, highly efficient production of hydrogen as sustainable energy receives great attention. In this work, bimetal-regulated In-based metal-organic framework (MOF) family is successfully designed and obtained. The most importance is that they exhibit high electrocatalytic and photocatalytic activities towards hydrogen generation from water. Such photo/electro-catalyst for efficiently producing hydrogen is a great challenge and requirement, which is also considered as the best way for green energy production. Herein, bimetallic indium-based MOFs is named as In/M-MOFs (M = Ni, Mn, Co, Fe and In). Among of them, In/Ni-MOF as electrocatalyst achieves a stable HER current with an extremely low overpotential of 215 mV at 10 mA cm−2 in 0.1 M KOH, and it as photocatalyst presents a superior hydrogen evolution efficiency of 1478.75 μmol·h−1·g−1 under full-range irradiation. These exciting results highlight great potential of In-based MOFs via bimetal regulation and control, and provide bright prospect for the construction of dual-functional green catalysts in the field of photo/electrocatalysis.

Modulating the band gap of a pyrazinoquinoxaline-based metal–organic framework through orbital hybridization for enhanced visible light-driven CN bond construction

An indium-based metal–organic framework bearing a pyrazinoquinoxaline derivative is synthesized to facilitate two methods for the construction of CN bonds, and their mechanisms are investigated through detailed theoretical calculations.

Highly efficient photoelectrochemical catalytic CO2 into formate with 2D indium-based metal-organic frameworks

Developing a universal and effective strategy to synthesize two-dimensional freestanding photosensitized metal–organic framework (MOF) still remains a challenge. In this study, we successfully synthesize a series of 2D porphyrin­based MOF through a simple and effictive solvothermal method. Owing to the special π-π conjugated structure of porphyrin rings, the as-synthesized indium-tetrakis(4-carboxyphenyl)-porphyrin (In-TCPP) is sensitive to visible light. The presence of light field effect plays an important role in enhanceing electrocatalytic carbon dioxide reduction reaction (CO2RR), resulting a impressive maximum formate Farady efficiency of 92 % at −1.0 V vs.RHE, which is 100 mV positive than 84 % of under dark condition. In addition, both current density and FEHCOOH obviously increases across the entire testing potential range when exposed to visible light irradiation. The decreased Tafel slope and electrochemical impedance under visible light indicate that the porphyrin macrocycles not only serve as the ligand but also as the light-switch to facilitate the electron transfer and decrease the energy barrier of electrochemical CO2RR. This work opens up a valuable guidance for photo-coupled electrochemical reduction of CO2 to HCOOH with low overpotential.

A signal amplification electrochemiluminescence biosensor based on Ru(bpy)32+ and β-cyclodextrin for detection of AFP

By combining two different materials, metal–organic frameworks (MOF) and β-cyclodextrins (β-CD), a signal amplification electrochemical luminescence (ECL) immunosensor was constructed to realize the sensitive detection of AFP. The indium-based metal–organic framework (In-MOF) was used as the carrier of Ru(bpy)32+, and Ru(bpy)32+ was immobilized by In-MOF through suitable pore size and electrostatic interaction. At the same time, using host–guest recognition, β-CD enriched TPA into the hydrophobic cavity for accelerating the electronic excitation of TPA, then, achieving the purpose of signal amplification. The signal amplification immunosensor structure is constructed among the primary antibody Ab1 connected to the Ru(bpy)32+@In-MOF modified electrode, AFP, BSA and the secondary antibody (Ab2) loaded with TPA-β-CD. The immunosensor has a good linearity in the range of 10-5 ng/mL-50 ng/mL, and the low limit of detection (LOD) is 1.1 × 10-6 ng/mL. In addition, the electrochemiluminescence immunosensor that we designed has strong stability, good selectivity and repeatability, which provides a choice for the analysis of AFP.

Large π-conjugated indium-based metal-organic frameworks for high-performance electrochemical conversion of CO2

Large π-conjugated indium-based metal-organic frameworks for high-performance electrochemical conversion of CO2

Hexaindium Heptasulfide/Nitrogen and Sulfur Co-Doped Carbon Hollow Microspindles with Ultrahigh-Rate Sodium Storage through Stable Conversion and Alloying Reactions.

Group IIIA-VA metal sulfides (GMSs) have attracted increasing attention because of their unique Na-storage mechanisms through combined conversion and alloying reactions, thus delivering large theoretical capacities and low working potentials. However, Na+ diffusion within GMSs anodes leads to severe volume change, generally representing a fundamental limitation to rate capability and cycling stability. Here, monodispersed In6 S7 /nitrogen and sulfur co-doped carbon hollow microspindles (In6 S7 /NSC HMS) are produced by morphology-preserved thermal sulfurization of spindle-like and porous indium-based metal organic frameworks. The resulting In6 S7 /NSC HMS anode exhibits theoretical-value-close specific capacity (546.2 mAhg-1 at 0.1Ag-1 ), ultrahigh rate capability (267.5mAhg-1 at 30.0Ag-1 ), high initial coulombic efficiency (≈93.5%), and ≈92.6% capacity retention after 4000 cycles. This kinetically favored In6 S7 /NSC HMS anode fills up the kinetics gap with a capacitive porous carbon cathode, enabling a sodium-ion capacitor to deliver an ultrahigh energy density of 136.3Whkg-1 and a maximum power density of 47.5kWkg-1 . The in situ/ex situ analytical techniques and theoretical calculation both show that the robust and fast Na+ charge storage of In6 S7 /NSC HMS arises from the multi-electron redox mechanism, buffered volume expansion, negligible morphological change, and surface-controlled solid-state Na+ transport.

A flexible indium-based metal-organic framework with ultrahigh adsorption capacity for iodine removal from seawater

The highly efficient removal of radioactive iodine from nuclear accident-polluted seawater is of great significance for the purpose of environmental protection. Herein, we report an indium-based metal–organic framework, named In-MOF, for highly efficient removing iodine from seawater. In-MOF is constructed by In3+ ions coordinated with tris (4-(1H-imidazol-1-yl) phenyl) amine and exhibits high chemical stability even under seawater for 30 days. Due to the flexible one-dimensional linear structure and high-density charged imidazolium groups, In-MOF possesses a high adsorption capacity (1138 mg/g) for iodine in water. Furthermore, it exhibits high selectivity in the presence of competitive ions, due to forming the unique I-π interactions between iodine and the In-MOF. Notably, these excellent adsorption features endowed In-MOF successfully remove iodine from seawater with a high removal rate of 93.86%. These results are of fundamental importance to understanding iodine uptake and designing materials with high adsorption capacity.

Cobalt ions induced morphology control of metal-organic framework-derived indium oxide nanostructures for high performance hydrogen sulfide gas sensors

Real-time gas sensors with high response and selectivity are highly desirable for hydrogen sulfide (H2S) monitoring concentration changes in the environment, especially at the ultra-trace level. Herein, cobalt-doped indium oxide (In2O3) with shorter-length nanorings was synthesized by foreign metal cobalt ions. By controlling the morphology of the material and calcinating the indium-based metal-organic frameworks (In-MOFs), the nanostructures of the obtained materials have a larger specific surface area, which further improves the sensing performance. The sensor prepared with a suitable amount of cobalt doping materials can exhibit the best gas-sensing performance. The Co-doped In2O3 sensor shows a high response to 2 ppm H2S (∼12.6) at 225 °C, low detection limits (100 ppb), and excellent selectivity, which is 5.34 times higher than pure In2O3 at 300 °C. Moreover, the potential growth mechanism speculates that the presence of Cobalt ions leads to a change in material morphology from nanorods to nanorings. This work provides an implementable method for controlling the morphology of the materials, which could facilitate the development of high-performance gas sensors.

Syntheses of ferrocene-functionalized indium-based metal–organic frameworks for third order nonlinear optical application

Presented here are a series of ferrocene-functionalized indium-based metal–organic frameworks (In-MOFs) with good third order nonlinear optical properties and redox activity.

Co2+ and nitrobenzene sensing using indium-based metal-organic framework

A highly stable indium-based metal-organic framework, namely [In(HTCA)(OH)]·2DMF·H2O (JOU-24), was solvothermally synthesized by using fluorescent ligand H3TCA (H3TCA = 4,4′,4″-tricarboxytriphenylamine). Single-crystal X-ray diffraction analyses show that JOU-24 displays two-dimensional framework based on infinite straight In-O-In chains. Further studies show that JOU-24 can keep its stability in water with pH range from 1 to 11. Thereafter, JOU-24 was developed as an excellent fluorescence sensor for selective detection of Co2+ and nitrobenzene (NB) in water due to its good fluorescence performance. For Co2+ sensing, a high quenching content is determined to be 24,500 with a low determine limit of 4.9 × 10−6 mol/L. For NB sensing, quenching content is 10230, which is also comparable to other reported MOFs. In addition, the mechanism for Co2+ and NB sensing is also proposed. This work shows a simple method to construct high-efficient fluorescence sensor for metal ions and nitroaromatics detection.

Indium-Based Metal-Organic Framework for Efficient Photocatalytic Hydrogen Evolution.

In this work, an indium-based metal-organic framework was successfully constructed, namely, as In-MOF, by elaborately selecting an InIII center with unique properties and a functional tetracarboxylic acid with unsaturated and open-coordinated nodes. Interestingly, the InIII center was connected to a single-metal-node-based porous three-dimensional pts net. Its structure was dentified by single-crystal and powder X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, etc. Considering the special luminescent characteristic of an indium-based framework, as-prepared In-MOF was explored as a photocatalyst for H2 production from water splitting. The testing results demonstrate that In-MOF as a promising photocatalyst with a suitable band gap realizes a H2 evolution efficiency of 777.65 μmol g-1 h-1.

Facile synthesis of amino-functionalized indium-based metal–organic frameworks and their superior light photocatalytic activity for degradation of tetracycline in water

The synthesized MIL-68(In)-NH2 photocatalyzed the degradation of tetracycline under visible light irradiation.

Bilateral Interfaces in In2Se3-CoIn2-CoSe2 Heterostructures for High-Rate Reversible Sodium Storage.

Metal selenides are considered as a group of promising candidates as the anode material for sodium-ion batteries due to their high theoretical capacity. However, the intrinsically low electrical and ionic conductivities as well as huge volume change during the charge-discharge process give rise to an inferior sodium storage capability, which severely hinders their practical application. Herein, we fabricated In2Se3/CoSe2 hollow nanorods composed of In2Se3/CoIn2/CoSe2 by growing cobalt-based zeolitic imidazolate framework ZIF-67 on the surface of indium-based metal-organic framework MIL-68, followed by in situ gaseous selenization. Because of the CoIn2 alloy phase in between In2Se3 and CoSe2, a heterostructure consisting of two alloy/selenide interfaces has been successfully constructed, offering synergistically enhanced electrical conductivity, Na diffusion process, and structural stability, in comparison to the single CoIn2-free interface with only two metal selenides. As expected, this nanoconstruction delivers a high reversible capacity of 297.5 and 205.5 mAh g-1 at 5 and 10 A g-1 after 2000 cycles, respectively, and a superior rate performance of 371.6 mAh g-1 at even 20 A g-1.

An interpenetrated anionic In(III)-MOF for efficient adsorption/separation of organic dyes and selective sensing of Fe3+ ion and nitroaromatic compounds

A microporous indium-based metal-organic frameworks (MOFs), namely [(CH3)2NH2]2 [In2(H3L)2(OX)]·3DMF·2H2O (JOU-23) (H3L ​= ​terphenyl-3, 4′, 5-tricarboxylic acid; OX ​= ​oxalic acid), have been solvothermal synthesized and characterized. Single-crystal X-ray diffraction show that JOU-23 displays three-dimensional anionic framework with 2-fold interpenetrated nets and rare topology. Due to its anionic and porous framework, JOU-23 can be developed for effective absorbing and separating cationic organic dyes. Further studies reveal that both the charge and size of dye molecules would affect the dyes’ absorption and separation. In addition, JOU-23 dispersed in dimethyl formamide shows strong emission at about 364 ​nm. Thus, it was developed as an efficient fluorescent sensor for probing Fe3+ ions and nitroaromatic compounds. The detection limit of Fe3+ is as low as 2 ​× ​10−6 ​M (KSV ​= ​59,755 ​M−1), which is excellent in MOFs fluorescent probe. At the same time, JOU-23 shows widespread sensing performance to nitroaromatic compounds. Especially, the detection ability of JOU-23 for nitrobenzene (NB) is good. Although the NB concentration reaches only 4.175 ​× ​10−5 ​M, the quenching efficiency can achieve 86.4%. Further studies show that the quenching performance of JOU-23 is mainly attributed to the competition of excitation light absorption and the absorption of emission light by measured objects. These results indicate that JOU-23 can be applied as a multifunctional material for organic dyes adsorption/separation, Fe3+ ions detection, and nitroaromatic compounds sensing.

Copper-indium hybrid derived from indium-based metal-organic frameworks grown on oxidized copper foils promotes the efficient electroreduction of CO2 to CO

This work reports a novel and effective method for the preparation of the copper-indium bimetallic electrocatalysts by the in situ growth of indium-based metal organic frameworks on oxidized copper foils as the precursor. Compared with the oxide-derived copper and the copper-based carbon material derivative grown in situ on oxidized copper foils, the as-prepared copper-indium electrocatalyst with a self-supporting structure, high roughness factor and rich lattice defects exhibits a superior CO Faradaic efficiency of 95% and good stability for the 36-h potentiostatic test at −0.6 V versus a reversible hydrogen electrode. Density functional theory calculations indicated that the indium atoms occupying the surface copper vacancy defects show lower free energy needed for the formation of *COOH and more difficult desorption of *H than indium atoms, supported on the perfect copper surface. Thereby, the copper-indium catalyst promotes CO2 electroreduction to CO and strongly inhibits hydrogen evolution.