Introduction to Chemical Adsorption Analytical Techniques and their Applications to Catalysis
Abstract The chemical adsorption isotherm reveals information about the active surface of a material and has been employed for many years as a standard analytical tool for the evaluation of catalysts. Temperature-programmed reaction techniques have emerged from the 1950’s as an indispensable companion to chemisorption isotherm analyses in many areas of industry and research. This […]
Characterization of Supported Palladium, Hydrogen Sorption
Introduction The ASAP 2020 Chemisorption instrument can be used for many different analyses. One of the uses of the 2020 can be to analyze the chemisorption of hydrogen onto supported metal catalysts. In this study, 5 weight % palladium on activated carbon was used. During chemisorption, the bonds between H2 molecules dissociate on the metal […]
Pulse Chemisorption with AutoChem II 2920: Isopropylamine on Zeolites
Introduction Several ZSM-5 zeolite samples were analyzed using the AutoChem II 2920. By pulsing isopropyl amine onto the zeolites, the concentration of acid sites can be determined for a particular zeolite. This is very important for catalytic reactions. For example, the reaction that occurred during these analyses proceeded through an intermediate due to an acid-base […]
Characterization of Vanadia Catalysts Supported on Different Carriers by TPD, TPR
Pham Thanh Huyen, Nguyen Anh Vu, Nguyen Minh Hien, Le Van Hieu, Dao Van Tuong, Hoang Trong Yem. Petrochemical and Catalysis Material Laboratory, Hanoi University of Technology, Hanoi, Vietnam Introduction Since V2O5/TiO2 catalysts were successful in the oxidation of oxylene, vanadium-containing catalysts were widely used in the oxidation of other aromatic and paraffinic hydrocarbons [1]. […]
The Heat of Adsorption of Hydrogen Gas on Lanthanum Pentanickel
by: Reid Davis Lanthanum pentanickel (LaNi5) is a metal alloy that, under the correct pressure and temperature conditions, will rapidly sorb hydrogen gas and form a metal hydride compound. Hydride forming metal compounds are well known for their ability to sorb large amounts of hydrogen gas at a specific pressure, store it, and later release […]
Gas Combinations for the AutoChem
The following is a list of typical gas combinations used with the AutoChem; recommended flow rates are also provided.
AutoChem and Mass Spectrometer Gas Calibration
The AutoChem TCD level calibration is a powerful tool for converting raw TCD signals to gas concentrations. This built-in calibration provides the AutoChem with known gas concentrations and records the TCD signal associated with each one. The concentration and signal data are then used to generate a polynomial for converting TCD signals to gas concentrations. […]
Thermocouple Calibration for the AutoChem – Thermostar Interface
Micromeritics’ AutoChem series of instruments is equipped with both digital and analog I/O (inputs/outputs), which may be used to control a Pfeiffer Vacuum Thermostar mass spectrometer via a single interface (Micromeritics’ part number 291/60811/00). This cable has been specifically designed to provide the hardware interface between the two instruments. The single-connector cable end is attached […]
Characterization of Acid Sites Using Temperature-Programmed Desorption
Temperature-Programmed Desorption (TPD) is one of the most widely used and flexible techniques for characterizing the acid sites on oxide surfaces1-5. Determining the quantity and strength of the acid sites on alumina, amorphous silica-alumina, and zeolites is crucial to understanding and predicting the performance of a catalyst. For several significant commercial reactions (such as n-hexane […]
Acid Site Characterization of NH4+ ZSM-5 (SiO2/Al2O3:30/1): A Pulse Chemisorption and TPD Application for the AutoChem
The Brønstead acidity of zeolites and other catalysts is of keen interest, as this affects the kinetics of reactions. Characterization of these sites is consequently very important and is often performed according to the ASTM D 4824 ammonia chemisorption method. An alternative, but comparable, characterization method involves pulse chemisorption of propylamines followed by a temperature […]
