BET SA and Microporous Materials - equipment/software for MOFs

Thread starter amanda
Start date Feb 29, 2024
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Surface area

Feb 29, 2024

amanda

TL;DR Summary: My lab is trying to apply BET SA to microporous materials (MOFs, Zeolites) - this doesn't work! I don't have the background to recommend a diff. approach or diff. equipment and I need help.

We've been measuring mesoporous material for years, but no one has the background to really dissect what the test does or what data is results in. We mainly just use it for comparisons.

We are newly working with MOF and trying to measure their surface area and pore volume. I've become our new expert after two hours of reading, but I just don't have the background to know what software/equipment/approach might work better. I've decreased our p/p0 range and seem to be getting okay results but I don't want to puzzle it out manually for every new material we screen.

I know Anton Paar has a system to get around this, but do you or another company have a better answer?

FAQ: BET SA and Microporous Materials - equipment/software for MOFs

What is BET surface area analysis?

BET surface area analysis is a method used to measure the surface area of materials, particularly porous materials like metal-organic frameworks (MOFs). It is based on the Brunauer-Emmett-Teller (BET) theory, which describes the physical adsorption of gas molecules on a solid surface. The surface area is calculated by measuring the amount of gas adsorbed at various pressures and using the BET equation to derive the specific surface area.

What equipment is typically used for BET surface area analysis?

The primary equipment used for BET surface area analysis is a gas adsorption instrument, often referred to as a BET analyzer. These devices can measure the adsorption of nitrogen or other gases at liquid nitrogen temperatures. Key components include a vacuum system, a temperature control unit, and a gas supply system to ensure accurate and controlled measurements.

What types of microporous materials can be analyzed using BET?

BET analysis is suitable for a wide range of microporous materials, including metal-organic frameworks (MOFs), zeolites, activated carbons, and certain types of porous organic polymers. These materials typically have pore sizes less than 2 nanometers and exhibit significant gas adsorption characteristics, making them ideal candidates for BET surface area measurements.

What software is commonly used for analyzing BET data?

Several software packages are available for analyzing BET data, including Micromeritics' ASAP software, Quantachrome's Nova software, and various open-source options like BETfit. These programs facilitate the input of raw data, apply the BET equation, and generate surface area and pore size distribution results, often with user-friendly interfaces for data interpretation.

How do I prepare a sample for BET surface area analysis?

Sample preparation for BET surface area analysis typically involves drying the material to remove moisture and other adsorbates. This can be achieved through vacuum drying or heating under inert gas. Once dried, the sample is often degassed prior to analysis to ensure that only the desired gas is adsorbed during the measurement process, allowing for accurate surface area determination.