Micropore size distribution
Pore widths from about 0.35 to 1 nm (ultramicropores).
Useful forActivated carbons, zeolites, MOFsSurface, Particle & Porosity
CO2 Adsorption & Pore Size Analysis
Micropore analysis by CO₂ adsorption at 273 K
CO₂ adsorption at 0 °C probes the narrowest micropores of carbons, zeolites and MOFs. It gives micropore volume, pore size distribution and CO₂ uptake where nitrogen at 77 K struggles to reach.
1 test optionCO₂ at 273 K (0 °C)Pores ~0.35–1 nmTypical turnaround 5–7 working days
CO2 Adsorption & Pore Size Analysis measurement principleIllustrative
01 / Overview
What is CO2 Adsorption & Pore Size Analysis?
The degassed sample is held at 273 K and exposed to CO₂ in small pressure steps up to about 1 bar. The uptake isotherm is fitted with density functional or Dubinin models to give micropore volume and a size distribution for pores below about 1 nm.
At 77 K nitrogen diffuses very slowly into ultramicropores and can underestimate them. CO₂ at 0 °C has a similar molecular size but far more thermal energy, so it enters these pores quickly. It complements BET, which covers total surface area and mesopores.
02 / How it works
How it works
- 01
Pores are emptied
The sample is heated under vacuum to clear water and trapped gases from its micropores.
- 02
Held at 0 °C
The sample tube sits in a bath at 273 K, where CO₂ can enter pores too narrow for N₂ at 77 K.
- 03
CO₂ dosed up to ~1 bar
CO₂ is admitted in steps up to about 1 bar and the uptake at each pressure is recorded.
- 04
Pores sized by modelling
A density functional or Dubinin model converts the isotherm into micropore volume and size.
03 / What it measures
What it measures
Micropore volume
Volume of the narrowest pores, e.g. by the Dubinin–Radushkevich method.
Useful forAdsorbents, carbon molecular sievesCO₂ uptake capacity
Amount of CO₂ adsorbed at 273 K and ~1 bar, in mmol/g.
Useful forCarbon-capture sorbentsMicropore surface area
Surface area inside the narrowest pores, from the CO₂ isotherm.
Useful forMicroporous carbons, charsCO₂ adsorption isotherm
Uptake versus pressure at 273 K for comparing materials.
Useful forScreening new sorbents04 / Test options
Choose the CO2 Adsorption & Pore Size Analysis options you need
1 option · none added yet
05 / Sample requirements
Sample requirements
- Accepted forms
- Dry powders, granules or small pellets
- Quantity
- Typically 100–500 mg; more for weakly porous materials
- Thermal stability
- State the highest temperature the sample tolerates during degassing
- Reactivity
- Say if the sample chemisorbs CO₂, e.g. amine-functionalised sorbents
- Dry powder in a sealed, labelled vial
- State the maximum safe degassing temperature
- Mention amine or basic sites that react with CO₂
- No liquids, slurries or wet pastes
- No mixed samples in one vial
Hazardous or air-sensitive samples: mention it in your request, and attach the MSDS if you have one.
06 / Results & turnaround
Results & turnaround
What you receive
- CO₂ adsorption isotherm at 273 K
- Micropore volume and micropore surface area
- Pore size distribution (DFT or Dubinin model)
- CO₂ uptake at ~1 bar (mmol/g)
- Raw data files and report PDF
Turnaround & pricing
Typically 5–7 working days after samples reach the lab.
Price confirmed in your quotation, depending on user type, options and number of samples.
07 / Limitations
When CO2 Adsorption & Pore Size Analysis isn't the right fit
Mesopores and total BET surface area
Particle size of the powder
Crystal structure or phase
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