Phase-Sensitive Detection in Potential-Modulated in Situ Absorption and Probe Beam Deflection Techniques:  Theoretical Considerations

2001 ◽  
Vol 73 (3) ◽  
pp. 527-532 ◽  
Author(s):  
Ionel C. Stefan ◽  
Yuriy V. Tolmachev ◽  
Daniel A. Scherson
Keyword(s):  
Probe Beam ◽  
Sensitive Detection ◽  
Beam Deflection ◽  
Phase Sensitive ◽  
Phase Sensitive Detection ◽  
In Situ Absorption ◽  
Theoretical Considerations

scholarly journals CO2 Methanation over Rh/CeO2 Studied with Infrared Modulation Excitation Spectroscopy and Phase Sensitive Detection

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 601
Author(s):  
Felix Hemmingsson ◽  
Andreas Schaefer ◽  
Magnus Skoglundh ◽  
Per-Anders Carlsson
Keyword(s):  
Reaction Pathway ◽  
Sensitive Detection ◽  
Side Reactions ◽  
Co2 Methanation ◽  
Individual Contributions ◽  
Phase Sensitive ◽  
Phase Sensitive Detection ◽  
Modulation Excitation Spectroscopy ◽  
Modulation Excitation

Methane is a well-established fuel molecule whose production from CO 2 through methanation garners increasing interest as an energy storage solution. While often produced with Ni based catalysts, other metals are of interest thanks to higher robustness and activity-selectivity numbers. The Rh/CeO 2 catalyst has shown appreciable properties for CO 2 methanation and its structural dynamics has been studied in situ. However, the reaction pathway is unknown. Here, we present infrared modulation excitation spectroscopy measurements with phase sensitive detection of a Rh/CeO 2 catalyst adsorbate composition during H 2 pulsing (0–2 vol.%) to a constant CO 2 (0.5 vol.%) feed. Various carbonyl (CO) and carbonate (b-CO 3 /p-CO 3 ) ad-species clearly respond to the hydrogen stimulus, making them potential reaction intermediates. The different CO ad-species are likely intermediates for product CO and CH 4 but their individual contributions to the respective formations are not unambiguously ascertained. As for the carbonate dynamics, it might be linked to the reduction/oxidation of the CeO 2 surface upon H 2 pulsing. Formate (HCOO) ad-species are clearly visible but appear to be, if not spectators, linked to slow side reactions possibly also affected by CeO 2 redox processes.

Application of modulation excitation-phase sensitive detection-DRIFTS for in situ/operando characterization of heterogeneous catalysts

2019 ◽  
Vol 4 (5) ◽  
pp. 862-883 ◽  
Author(s):  
Priya D. Srinivasan ◽  
Bhagyesha S. Patil ◽  
Hongda Zhu ◽  
Juan J. Bravo-Suárez
Keyword(s):  
Fourier Transform ◽  
Heterogeneous Catalysts ◽  
Diffuse Reflectance ◽  
Sensitive Detection ◽  
Phase Sensitive ◽  
Phase Sensitive Detection ◽  
Modulation Excitation ◽  
General Method

A new more general method and guidelines for the implementation of modulation excitation-phase sensitive detection-diffuse reflectance Fourier transform spectroscopy (ME-PSD-DRIFTS).

Design, modelling, and application of a low void-volume in situ diffuse reflectance spectroscopic reaction cell for transient catalytic studies

2019 ◽  
Vol 4 (4) ◽  
pp. 667-678 ◽  
Author(s):  
Bhagyesha S. Patil ◽  
Priya D. Srinivasan ◽  
Ed Atchison ◽  
Hongda Zhu ◽  
Juan J. Bravo-Suárez
Keyword(s):  
Fourier Transform ◽  
Diffuse Reflectance ◽  
Fourier Transform Spectroscopy ◽  
Void Volume ◽  
Sensitive Detection ◽  
Reaction Cell ◽  
Phase Sensitive ◽  
Phase Sensitive Detection ◽  
Modulation Excitation

A new low void-volume in situ reaction cell enables application of modulation excitation-phase sensitive detection-diffuse reflectance Fourier transform spectroscopy (ME-PSD-DRIFTS).

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