Chapter: Chemical Adsorption
Physical and chemical adsorption differentiated
Theory
 Chemisorption and its energies
Classical theories of chemical adsorption isotherms
-- Langmuir theory
-- Freundlich and Temkin isotherms
Analysis and data reduction
Static volumetric
-- Isolating the chemisorption isotherm
-- Chemisorption monolayer volume
-- Number of accessible active sites
-- Metal dispersion
-- Active metal area
-- Active particle size
-- Isosteric heat of adsorption
Dynamic technique: pulse chemisorption
Temperature-programmed reactions
Temperature-programmed reduction
Temperature-programmed desorption
Temperature-programmed oxidation
Instrumentation
Dynamic (flowing gas) instruments
Instrumentation for the study of temperature-programmed reactions
-- Relation of function to valves and flow paths
-- Temperature controlled internal modules
-- Temperature monitoring
-- Thermal conductivity detector
-- Response times and synchronization
-- Subambient analysis
-- Monitoring and controlling gas flow
-- Mixed gases
-- Vapor generation
Static volumetric chemisorption analyzer
-- Gas delivery system
-- Materials of construction
-- Sample holder assembly
-- Sample temperature
-- Sample degassing, pretreatment, and analysis
Analytical techniques and data reduction methods
Measurement of surface acidity by ammonia titration
TPD applied to the distribution of acid site strength
Determination of isosteric heat of adsorption
Active Surface area and percent dispersion
of metal oxides by the dynamic technique
Sample preparation
Analysis
Data reduction
-- Quantifying reaction gas volumes
-- Specific volume chemisorbed
-- Total volume of nitrogen produced
-- Surface area of copper
-- Metal dispersion
Temperature-programmed techniques
-- TPR of metals on AlO 2
-- TPD of H 2 from reduced Pt on Al 2 O 3
-- TPD of ammonia on ZSM-5 zeolite
-- TPR of CuO
-- TPR of Fe 2 O 3
-- TPR method for characterizing the interaction
between active metal and support
-- TPR applied to the formation of alloys
-- TPR applied to the study of promoters in bimetallic catalysts
Symbols used in this chapter
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