Forty years of temporal analysis of products

Abstract

A detailed understanding of reaction mechanisms and kinetics is required in order to develop and optimize catalysts and catalytic processes. While steady-state investigations are known to give a global view of the catalytic system, transient studies are invaluable since they can provide more comprehensive insight into elementary steps. For almost forty years temporal analysis of products (TAP) has been successfully utilized for transient studies of gas phase heterogeneous reactions, and there have been a number of advances in instrumentation and numerical modeling methods in that time. Since TAP is a complex methodology it is often viewed as a niche specialty. With the purpose to make TAP more relevant and approachable to a wider segment of the catalytic research community, part of the intention of this work is to highlight the significant contributions TAP has made to elucidating mechanistic and kinetic aspects of complex, multistep heterogeneous reactions. With this in mind, an outlook is also disclosed for the technique in terms of what is needed to revitalize the field and make it more applicable to the recent advances in catalyst characterization (e.g. operando modes).

Transient Kinetic Experiments within the High Conversion Domain: The Case of Ammonia Decomposition

“…The temporal analysis of products (TAP) reactor [8][9][10] is a third type of kinetic device that investigates materials at conditions far from equilibrium and has not been as widely adopted as PFR and CSTR. In contrast to the PFR and CSTR, which are reactors with convective transport, the TAP device is an example of a pure-diffusion reactor.…”

Unraveling the H2 Promotional Effect on Palladium-Catalyzed CO Oxidation Using a Combination of Temporally and Spatially Resolved Investigations

“…In order to investigate the elementary steps of the reactions, a transient pulse response methodology was employed using a TAP reactor. 21 − 25 This technique has been proven to provide key insights into elementary steps of catalytic processes. 26 , 27 However, despite the ability to screen varying oxidation states via multi-pulse experiments, 28 TAP is not typically used to determine structure–activity correlations.…”

Alcohol Synthesis from CO2, H2, and Olefins over Alkali‐Promoted Au Catalysts—A Catalytic and In situ FTIR Spectroscopic Study

“…CO was used as ap robe molecule for characterizing the Au NPs. At the end of the experiment, the cell was flushed with N 2 while the pressure was decreased to 10 5 Pa. AT AP-2 (temporal analysis of products) reactor operating at microsecond time resolution [50,52,53] was used to investigate the interaction of CO 2 ,C O, C 2 H 4 ,a nd H 2 by using fresh and used (270 ho n stream at 200-250 8Cu sing various feeds containing CO 2 ,H 2 and C 2 H 4 )c atalysts. The reaction cell was equipped with CaF 2 windows and connected to ag as-dosing and evacuation system.…”

“…Then, the reaction cell was cooled down to 200 8Ca nd the following gas mixtures were each successively dosed for 60 min:C 2 H 4 /N 2 ,H 2 /C 2 H 4 /N 2 and CO 2 /H 2 / C 2 H 4 /N 2 (10 vol %o feach gas in N 2 ,r espectively). At the end of the experiment, the cell was flushed with N 2 while the pressure was decreased to 10 5 Pa. AT AP-2 (temporal analysis of products) reactor operating at microsecond time resolution [50,52,53] was used to investigate the interaction of CO 2 ,C O, C 2 H 4 ,a nd H 2 by using fresh and used (270 ho n stream at 200-250 8Cu sing various feeds containing CO 2 ,H 2 and C 2 H 4 )c atalysts. The catalyst sample (70 mg) was filled into the isothermal zone of the quartz reactor (internal diameter = 6mma nd length = 40 mm) for each measurement.…”