Temperature Programmed Reduction Using the AutoChem
Temperature-programmed reduction (TPR) is a widely used tool for the characterization of metal oxides, mixed metal oxides, and metal oxides dispersed on a support. The TPR method yields quantitative information of the reducibility of the oxide’s surface, as well as the heterogeneity of the reducible surface. TPR is a method in which a reducing gas […]
Accuracy of Vapor Dosing with the AutoChem
The Vapor Generator option for the AutoChem provides a means to quantitatively inject pulsed dose amounts of vapor onto a solid sample. Vapors of most interest are actually gases below their critical temperature; hence, they are condensable. Design features and operation of the AutoChem’s vapor generator are described in Product Bulletin 83. Reagent grade 2-propanol […]
Acid Site Characterization of H+ ß (SiO2/Al2O3:75/1): 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-programmed […]
An Introduction to Chemical Adsorption Analytical Techniques and Methods (Condensed Version)
Author: Paul A. Webb This article is a condensed version of a more comprehensive article titled “Chemical Adsorption,” as an Analytical Technique. Introduction Catalysts are used in a variety of applications from the production of consumer goods to the pro-tection of the environment. Optimum design and efficient utilization of catalysts requires a thor-ough understanding of […]
Autochem III – Catalyst and Active Surface Characterization
The AutoChem from Micromeritics is the most widely used and highly cited system for catalyst reactivity characterization because it is also the most automated, highly accurate system for chemisorption and temperature-programmed reactions. The all-new AutoChem III meets and exceeds that performance with a design that will save you hours a day, make the most sensitive, […]
Ammonia TPD for Heat Sensitive Materials on the Autochem III
Introduction Zeolites are extensively used in many applications as ion exchange agents, adsorbents, and catalysts. Characterizing the acidity of a zeolite is important to design and optimize it for a catalytic activity of interest. Among many methods developed for characterizing the acid sites of a zeolite, the Temperature Programmed Desorption technique is one of the […]
Breakthrough Analysis on the AutoChem
Introduction The AutoChem is a flow-through system that allows for the characterization of catalysts for surface activity. The AutoChem can also function as a basic single component breakthrough unit allowing for carrier, preparation, and analysis gas flows. This document will describe how to perform a breakthrough analysis using the AutoChem alongside a mass spectrometer. Experimental […]
Effect of O2 Traces in the Carrier Gas on Quantifying the Active Species in Catalysts
Determination of the dispersion of active species on catalysts is a tremendous tool to discover and predict the activity of the catalyst. Thus, dispersion of active species indicate the quantity of active particles located on the surface of a catalyst that are accessible and have a direct contact with the reactant molecules that have to […]
Frontiers in Catalysis Design for Sustainable Technologies
Confront the challenges of catalysis characterization. Heterogeneous catalysis is quite possibly the most relevant discipline in the chemical industry, spearheading improvements in process sustainability by improving the exploitation of raw materials, enabling the transition from fossil to renewable feedstocks, reducing energy consumption, and minimizing the environmental footprint. To confront these challenges head on, this vibrant […]
Intermetallics with Isolated Metal Ensembles Define Active Site Requirements and Dictate Catalytic Selectivity during Semi-hydrogenation
A reliable method to design site-isolated metal catalysts is through the synthesis of intermetallic bulk compounds where a small number of active atoms are isolated in an inert matrix of a second metal. Unlike alloys, intermetallics have long range periodic atomic order and are more likely resistant to surface segregation effects making them an ideal […]
