BET testing is based on the multi-molecular layer adsorption model proposed by S. Brunauer, P. H. Emmett, and E. Teller (BET equation). Linear fitting of the BET equation allows calculation of the monolayer saturation adsorption capacity ( V_m ), from which the specific surface area of the sample is obtained using the Langmuir specific surface area calculation formula.
Application Fields
- Material R&D: Characterizes specific surface area and pore structure of catalysts, adsorbents, and nanomaterials to evaluate active sites and adsorption performance.
- Energy Sector: Analyzes pore characteristics of battery electrode materials and hydrogen storage materials to optimize material design.
- Environmental Science: Studies pore size distribution of environmental materials (e.g., activated carbon, molecular sieves) for pollutant adsorption processes.
- Geological Research: Measures pore parameters of soil and rocks to analyze permeability and water storage capacity.
Instrument Models and Technical Parameters
- Instrument model: TriStar II 3020
- Technical parameters:
- Porosity: 3.5–5000 Å
- Pore size: 2 nm–200 nm
- Specific surface area: 0.1–3500 m²/g
- Measurement repeatability: <±3%
Sample Submission Requirements and Notes
- Samples must be dry solids; liquid or colloidal samples are prohibited.
- Sample mass should be 200–1000 mg, placed in a clean plastic centrifuge tube and sealed with a label.
- Samples should be free of moisture, low-molecular-weight organic compounds (e.g., ethanol, acetone), and volatile impurities to prevent pipeline blockage or adsorption signal interference.
- Impure samples must be purified in advance (e.g., vacuum drying, extraction).
- Samples must remain stable at the pretreatment temperature without decomposition, polymerization, or other chemical reactions. Provide thermal decomposition temperature and chemical properties to select suitable pretreatment conditions (e.g., degassing temperature, time).
BET Test Case
Testing Standards
- ISO 9277:2022 Determination of the specific surface area of solids by gas adsorption - BET method
- GB/T 19587-2017 Determination of specific surface area of solid materials by gas adsorption BET method
