Alfa Chemistry offers Brunauer-Emmett-Teller (BET) surface area analysis testing to accurately characterize the specific surface area and its porous geometry in 2D materials such as graphene, which is essential for understanding their properties and applications. Contact us today so we can help you with your 2D material testing!
Why BET Specific Surface Area Analysis
Most of the atoms in a nanomaterial are present on its surface, and it is these atoms that usually determine the properties of the particles. Therefore, the measurement of specific surface area (SSA) is often critical to understanding the behavior of nanomaterial systems. Surface area measurements are usually of accessible surfaces and are determined using gas adsorption methods. BET gas adsorption is the most common method for determining SSA of nanomaterials.
BET surface area analysis is a multi-point measurement of the specific surface area (m2/g) of an analyte by gas adsorption analysis in which an inert gas flows continuously through a solid sample or a solid sample is suspended in a defined volume of gas. Due to the weak van der Waals forces, small gas molecules adsorb onto the solid matrix and its porous structure, forming a single layer of adsorbed gas. This monolayer and adsorption rate can be used to calculate the specific surface area of a solid sample and its porous geometry. Alfa Chemistry has prepared a series of surface area analyzers to perform multi-point measurements on customers' solid samples based on BET adsorption isotherms.
Fig 1. Schematic of the adsorption of gas molecules onto the surface of a sample showing (a) the monolayer adsorption model assumed by the Langmuir theory and (b) the multilayer adsorption model assumed by the BET theory.
The BET method is a fast and inexpensive method that can be used to perform relative measurements of SSA on a large number of nanomaterials with strict attention to sample preparation and calibrator implementation details where possible.
Service Detail
| Testing Services | BET Specific Surface Area Analysis |
| Test Content | Mesoporous/Microporous/Macroporous Materials Pore Size Distribution, Specific Surface Area Analysis |
| Sample Type | Powder / Film / Bulk |
| Instrument Model | Mike2020, Horiba SA-9600, Quantachrome AUTOSORB IQ, Quantachrome QUADRASORB SI |
| Lead Time | 2~3 Weeks |
XRF Sample Preparation Consulting
Sample preparation is important in gas adsorption experiments. Prior to analysis, samples must be pretreated for adsorbed gases, water or other surface "impurities" that may affect gas adsorption in a process called degassing or degassing. We typically do this by applying high temperatures to the sample as well as a vacuum or continuous flow of inert gas.
A limitation of this measurement technique is that it can only be used on dry samples, as aggregation/clustering may result in lower SSA values reported for tightly bound nanomaterials, which may require a de-agglomeration or fractionation process on the dry sample prior to analysis to increase the accessible surface area. Alfa Chemistry can provide advice on the most appropriate method for your material type and analytical requirements.
Our requirements for samples are as follows:
- For bulk/film sample: Length/width/thickness < 5 mm.
- For powder sample:
If SSA<500 m2/g, provide >100 mg.
If SSA<100 m2/g, provide >200 mg.
If SSA<10 m2/g, provide >0.5~1 g.
You can also use this formula to determine the weight required for each sample: Sample Weight (g) = 15 / SSA
- If you do not know SSA, please prepare samples according to the table below.
| Pore size | Number of samples to provide |
|---|
| Macropores and micropores | >100 mg |
| Mesoporous | >250 mg |
Note:
- Use centrifuge tubes for powder samples.
- Please grind your samples before shipping to us. Generally, the particle size should be less than 3 mm.
- If the sample size is insufficient and the accuracy of the results cannot be guaranteed, we do not provide free retests.
- All samples are non-refundable, please contact us if you have special requirements.
Please kindly note that our products are for research use only.
