Description

Key Properties & Advantages
MIL-101(Cr)’s enduring utility stems from its engineered structure and chromium-based chemistry:

Exceptional Porosity: Boasts one of the highest BET surface areas among MOFs (typically 2500–4000 m²/g) and a hierarchical pore network (micropores ~0.8 nm, mesopores ~2.9 nm and ~3.4 nm). This structure enables efficient mass transport and high adsorption capacity for molecules of varying sizes.
Remarkable Chemical Stability: Maintains structural integrity in water (pH 2–12), organic solvents, and elevated temperatures (up to 300°C), outperforming most MOFs in harsh operational environments—critical for industrial scalability.
Superior Water Vapor Adsorption: Exhibits strong affinity for water molecules, making it ideal for humidity control, water harvesting, and adsorption-based cooling systems.
Charge Transfer Capability: Chromium(III) nodes facilitate electron transfer, enhancing performance in catalytic and electrocatalytic reactions by stabilizing intermediates and promoting redox activity.
Tunable Surface Chemistry: Supports post-synthetic modification (e.g., functional group grafting, metal doping) to tailor selectivity for specific gases, pollutants, or reactants—expanding its versatility for targeted applications.
Core Applications
Gas Storage & Separation/Purification
MIL-101(Cr)’s porosity and stability make it a leading choice for gas-related applications:

High-Capacity Gas Storage: Efficiently stores gases such as H₂, CH₄, and CO₂, supporting clean energy initiatives (e.g., hydrogen fuel storage, natural gas compression alternatives).
Selective Gas Separation: Separates mixed gases (e.g., CO₂/N₂, C₂H₄/C₂H₆) via size exclusion and affinity-based adsorption, critical for carbon capture, natural gas purification, and petrochemical processing.
Catalysis & Photocatalysis
Its ability to adsorb reactants and facilitate charge transfer drives performance in energy and environmental catalysis:

Electrocatalysis: Serves as a catalyst or support for reactions like oxygen reduction (ORR), hydrogen evolution (HER), and CO₂ electroreduction, leveraging chromium nodes and high surface area to enhance activity and durability.
Photocatalysis: Promotes light-driven reactions such as water splitting for H₂ production and pollutant degradation (e.g., dyes, pharmaceuticals), with tunable surface chemistry enabling visible-light responsiveness.
Pollutant Adsorption & Environmental Remediation
MIL-101(Cr) excels in removing contaminants from air and water:

Water Purification: Adsorbs heavy metal ions (e.g., Pb²⁺, Hg²⁺), organic pollutants (e.g., pesticides, industrial dyes), and pharmaceuticals via pore confinement and ligand-metal interactions, achieving high removal efficiencies even at low concentrations.
Air Purification: Captures volatile organic compounds (VOCs), toxic gases (e.g., H₂S, NOₓ), and particulate matter, supporting indoor air quality control and industrial emission treatment.
Mixed-Matrix Membranes & Sensing
Mixed-Matrix Membranes (MMMs): Embedded in polymer membranes to enhance gas separation efficiency (e.g., CO₂/CH₄) and mechanical stability, outperforming pure polymer membranes in industrial separation processes.
Sensing & Detection: Functionalized MIL-101(Cr) acts as a sensor platform for detecting gases (e.g., toxic industrial chemicals), heavy metals, or biomolecules via changes in fluorescence, conductivity, or adsorption behavior—enabling real-time monitoring in environmental and clinical settings.
Technical Specifications
Parameter Details
Chemical Composition Chromium(III) oxide clusters linked by terephthalate ligands (Cr₃O(OH)(H₂O)₂(bdc)₃, where bdc = 1,4-benzenedicarboxylate)
Appearance Pale green to blue-green crystalline powder
BET Surface Area 2500–4000 m²/g
Pore Structure Hierarchical (micropores + mesopores: ~0.8 nm, ~2.9 nm, ~3.4 nm)
Thermal Stability Up to 300°C (inert atmosphere)
pH Stability 2–12 (aqueous solutions)
Water Adsorption High capacity (typically 1.2–1.8 g H₂O/g at 90% RH)
Quality Assurance
MIL-101(Cr) undergoes rigorous characterization to ensure performance consistency:

X-ray diffraction (XRD) to confirm structural integrity and phase purity.
Nitrogen adsorption-desorption analysis to verify surface area and pore size distribution.
Thermal gravimetric analysis (TGA) to validate stability under elevated temperatures.
Stability testing in aqueous solutions (varying pH) and organic solvents.