Kinetics of Co oxidation over unloaded and pd-loaded α-Fe2 O3 spherical submicron powder catalysts: Photoacoustic investigations at low pressure

Joong Seok Roh, Ji Yeong Kim, Joong Gill Choi, Sung Han Lee

Research output: Contribution to journalArticle

Abstract

In this study, α-Fe2 O3 spherical particles with an average diameter of approximately 200 nm were synthesized by a solvothermal method for use as both a catalyst and medium for a Pd catalyst. The kinetics of CO oxidation over powders of α-Fe2 O3 spherical particles and 14 wt % Pd/α-Fe2 O3 spherical particles were measured in a static reactor by using a CO2 laser-based photoacoustic technique. The total pressure was fixed at 40 Torr for the CO/O2/N2 mixture for temperatures in the range of 225–350 C. The variation in the CO2 photoacoustic signal with the CO2 concentration during CO oxidation was recorded as a function of time, and the CO2 photoacoustic data at the early reaction stage was used to estimate the rates of CO2 formation. Based on plots of ln(rate) vs. 1/T, apparent activation energies were calculated as 13.4 kcal/mol for the α-Fe2 O3 submicron powder and 13.2 kcal/mol for the 14 wt % Pd/α-Fe2 O3 submicron powder. Reaction orders with respect to CO and O2 were determined from the rates measured at various partial pressures of CO and O2 at 350 C. The zero-order of the reaction with respect to Po2 was observed for CO oxidation over α-Fe2 O3 submicron powder, while 0.48 order to Po2 was observed for CO oxidation over Pd/α-Fe2 O3 submicron powder. The partial orders with respect to PCO were determined as 0.58 and 0.54 for the α-Fe2 O3, and the Pd/α-Fe2 O3 submicron powders, respectively. The kinetic results obtained from both catalysts were compared with those for the α-Fe2 O3 fine powder catalysts and were used to understand the reaction mechanism.

Original languageEnglish
Article number98
JournalCatalysts
Volume8
Issue number3
DOIs
Publication statusPublished - 2018 Mar

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Photoacoustic effect
Carbon Monoxide
Powders
low pressure
catalysts
Oxidation
oxidation
Catalysts
Kinetics
kinetics
Partial pressure
partial pressure
Activation energy
plots
reactors
activation energy
Lasers
estimates
lasers

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Physical and Theoretical Chemistry

Cite this

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title = "Kinetics of Co oxidation over unloaded and pd-loaded α-Fe2 O3 spherical submicron powder catalysts: Photoacoustic investigations at low pressure",
abstract = "In this study, α-Fe2 O3 spherical particles with an average diameter of approximately 200 nm were synthesized by a solvothermal method for use as both a catalyst and medium for a Pd catalyst. The kinetics of CO oxidation over powders of α-Fe2 O3 spherical particles and 14 wt {\%} Pd/α-Fe2 O3 spherical particles were measured in a static reactor by using a CO2 laser-based photoacoustic technique. The total pressure was fixed at 40 Torr for the CO/O2/N2 mixture for temperatures in the range of 225–350◦ C. The variation in the CO2 photoacoustic signal with the CO2 concentration during CO oxidation was recorded as a function of time, and the CO2 photoacoustic data at the early reaction stage was used to estimate the rates of CO2 formation. Based on plots of ln(rate) vs. 1/T, apparent activation energies were calculated as 13.4 kcal/mol for the α-Fe2 O3 submicron powder and 13.2 kcal/mol for the 14 wt {\%} Pd/α-Fe2 O3 submicron powder. Reaction orders with respect to CO and O2 were determined from the rates measured at various partial pressures of CO and O2 at 350◦ C. The zero-order of the reaction with respect to Po2 was observed for CO oxidation over α-Fe2 O3 submicron powder, while 0.48 order to Po2 was observed for CO oxidation over Pd/α-Fe2 O3 submicron powder. The partial orders with respect to PCO were determined as 0.58 and 0.54 for the α-Fe2 O3, and the Pd/α-Fe2 O3 submicron powders, respectively. The kinetic results obtained from both catalysts were compared with those for the α-Fe2 O3 fine powder catalysts and were used to understand the reaction mechanism.",
author = "Roh, {Joong Seok} and Kim, {Ji Yeong} and Choi, {Joong Gill} and Lee, {Sung Han}",
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Kinetics of Co oxidation over unloaded and pd-loaded α-Fe2 O3 spherical submicron powder catalysts : Photoacoustic investigations at low pressure. / Roh, Joong Seok; Kim, Ji Yeong; Choi, Joong Gill; Lee, Sung Han.

In: Catalysts, Vol. 8, No. 3, 98, 03.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Kinetics of Co oxidation over unloaded and pd-loaded α-Fe2 O3 spherical submicron powder catalysts

T2 - Photoacoustic investigations at low pressure

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AU - Lee, Sung Han

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