Micromeritics Chemisorption Expertise

We offer high-performance chemisorption analyzers, supported by expert application scientists, for evaluating surface active sites, adsorption strength, and the reactivity of powders and particulate materials.

What is Chemisorption?

Chemisorption, or chemical adsorption, is a surface phenomenon where a chemical reaction occurs between the adsorbate (gas or vapor) and the exposed surface of a solid material. This process results in the formation of a strong bond via electron sharing and valence bonding, creating a distinct chemical species at the surface. Unlike physical adsorption, chemisorption is highly specific, involving the splitting of adsorbing gas or vapor molecules into atoms, radicals, or ions that chemically bond to specific adsorption sites on the surface.

This interaction is typically characterized by a high binding energy and is irreversible under standard conditions. Chemisorption plays a vital role in catalyst characterization, providing key insights into properties such as the reduction temperature at which metals become catalytically active, the quantity of surface metal or active species available for reaction, the strength of specific active sites, and the material’s performance after undergoing reduction or oxidation cycles.

Pulse 1 / Stage 1 = Fully absorbed

Pulse 2 / Stage 2 = Partially saturated

Pulse 3 / Stage = Fully saturated

Chemisorption Instruments

We offer two instrumental techniques for chemisorption analysis, the static volumetric technique and the dynamic (flowing gas) technique. The static chemisorption technique is performed by both the Micromeritics 3Flex, and the ASAP 2020 Plus, which operates over a range of pressures. The dynamic chemisorption technique is utilized by the 3Flex, ChemiSorb, and AutoChem series of instruments. These three instruments utilize pulse chemisorption in a dynamic flow system to titrate the active surface.

Static Chemisorption

In static adsorption, generally two adsorption ‘isotherms’ (quantity of gas adsorbed as a function of pressure at constant temperature) are collected at sub-atmospheric pressures: the first representing total adsorption, the second representing reversible adsorption, and the difference between the two representing the irreversible adsorption (i.e. ‘chemisorption’). This technique provides information on the quantity of adsorption sites, from which subsequent calculations may be done. When the active surface area analysis is performed at one specific temperature, it is called isothermal chemisorption.

Dynamic Chemisorption

In dynamic chemisorption, the identity, quantity, and strength of active sites can be quantified by adsorption, desorption, or reaction under isothermal or temperature programmed conditions. Dynamic chemisorption utilizes a variety of techniques such as temperature programmed reduction (TPR), oxidation (TPO), desorption (PTD), and pulse chemisorption to characterize active sites in materials.

For the dynamic system, depending on the experiment, a lower concentration of active gas may be in contact with the sample for only a few seconds. Depending on the sample, equilibration and access of the active gas to the adsorption sites of interest may be faster in the static system.

Our Solutions

Instruments

AutoChem III

The premier instrument for dynamic chemisorption of heterogenous catalysts by pulse chemisorption and temperature-programmed reactions (TPR, TPD, TPSR, TPO).

3Flex

Static and dynamic chemisorption combined with the most advanced high-vacuum gas adsorption measurements for complete surface characterization of porous materials.

ASAP 2020 Plus

End-to-end surface characterization from sample prep to physical and chemical adsorption measurements.

ICCS Catalyst Characterization

Perform in situ measurements of catalyst characteristics by integrating the ICCS with a flow reactor system

Flow Reactor (FR)

De-risk new catalyst and process scale-up by demonstrating and optimizing performance under process conditions in an automated benchtop flow reactor.

ChemiSorb HTP

High-throughput static chemisorption for reliable screening and process control

Services

We provide a comprehensive range of characterization services whether it is the analysis of a single sample, a complex method development or validation, new product assessments, or addressing large-scale manufacturing projects.

Available options

Chemisorption Tests:

Volumetric Chemisorption analysis
Dynamic or pulse Chemisorption analysis
Pulse Chemisorption using liquid vapors

Temperature-Programmed Studies:

Temperature-Programmed Reduction (TPR)
Temperature-Programmed Desorption (TPD)
Temperature-Programmed Oxidation (TPO)

Other Chemisorption Experiments:

Heat of Desorption, first order Kinetics
Isosteric Heat of Adsorption

FAQ

What is a chemisorption analyzer?

A chemisorption analyzer is a sophisticated scientific instrument used to measure the interaction between a solid surface and gas molecules, particularly focusing on chemical bonding. It plays a crucial role in various industries such as catalysis, material science, and environmental monitoring by providing detailed insights into surface properties and reaction mechanisms. Chemisorption analyzers utilize precise techniques like temperature-programmed desorption (TPD), temperature-programmed oxidation (TPO), temperature-programmed surface reactions (TPSR), and pulse chemisorption to characterize catalysts, adsorbents, and nanoparticles, aiding in the development of advanced materials and optimized processes.
What are the techniques of chemisorption?

The techniques of chemisorption encompass a range of sophisticated methods employed in scientific research and industrial applications. These techniques include temperature-programmed desorption (TPD), temperature-programmed oxidation (TPO), temperature-programmed surface reactions (TPSR), and pulse chemisorption. Each technique offers unique insights into the interaction between solid surfaces and gas molecules, aiding in the characterization of catalysts, adsorbents, and nanomaterials. By employing these advanced techniques, researchers and engineers can gain valuable information essential for optimizing processes and developing innovative materials across various industries.
How much sample to use?/What is the correct sample size?

As of the latest developments, the current sample size for chemisorption analysis varies depending on the specific instrument and application requirements. However, modern chemisorption analyzers typically accommodate sample sizes ranging from a few milligrams to several grams. These versatile instruments are capable of analyzing a wide range of materials, including catalysts, adsorbents, and nanoparticles, offering researchers and engineers the flexibility needed for comprehensive surface characterization and reaction studies. By leveraging the appropriate sample size, scientists can obtain accurate data crucial for optimizing processes and advancing research in fields such as catalysis, material science, and environmental monitoring.