Hickenlooper, JL
1998
Determination of Rh-CO Integrated Absorption Coefficients as a Function of Temperature and Coverage for ZSM-5 Supported Rhodium
Hickenlooper, J.L.
Determination of Rh-CO Integrated Absorption Coefficients as a Function of Temperature and Coverage for ZSM-5 Supported Rhodium, M.S./BYU, April 1998. Advisor: Hecker
1997
Catalyst Characterization by Quantitative FTIR: Determination of Rh-CO Extinction Coefficients for Rh/ZMS-5
Hickenlooper, J.L. and Hecker, W.C.
Environmental Catalysis II, (in press), 1997. Also presented at the AIChE Annual Meeting, Los Angeles, California, November 17, 1997. Funded in part by ACERC.
The application of quantitative FTIR to heterogeneous catalysis allows the determination of surface concentrations of active intermediates. Successful application of quantitative FTIR depends upon understanding the factors affecting integrated extinction coefficients. Extinction coefficients relate integrated IR absorbance to surface concentration. Research on catalyst systems with 1% Rh has determined the Rh-CO extinction coefficients are not dependent upon oxide support, using the following supports: SiO2, Al2O3, Ce/SiO2, Ce/Al2O3, TiO2, and MgO. In addition, varying temperatures between 50° and 200°C and varying weight loadings from 0.2% to 9% appeared to have no effect on the extinction coefficients for Rh/SiO2 catalysts. Similar studies are being carried out on Rh/ASM-5. The following band frequencies have been observed on 0.8% Rh/AMS-5 catalyst: 2181 and 2150 cm^-1, 2100 (sh) and 2020 (sh) cm^-1, 2114, and 2048 cm^-1, 2117 and 2083 cm^-1 and 2069 cm^-1. The two weak bands at 2181 and 2150 cm^-1 are assigned to Rh (III)-CO where CO is bonded reversibly to the Rh(III) ion (Shannon et al. 1984). The bands at 2100 (sh) and 2020 (sh) cm^-1, 2114, and 2048 cm^-1, 2117 and 2083 cm^-1 are assigned to three types of RH(I) carbonyls (Shannon et al. 1984). The band at 2069 cm^-1 is proposed to be a linear Rh-CO species. Extinction coefficients for these Rh-Co species are being determined by combining peak areas from IR placed in a high temperature transmission reactor cell. The effects of temperature on the extinction coefficients for CO chemisorbed on Rh/ZMS-5 are also being determined. The results of this study will allow catalysis researched to apply quantitative FTIR to better understand catalytic surface reaction or Rh/ZMS-5 as well as demonstrate the use of an analytical system for determining extinction coefficients.
Hickenlooper, JL
1998
Determination of Rh-CO Integrated Absorption Coefficients as a Function of Temperature and Coverage for ZSM-5 Supported Rhodium
Hickenlooper, J.L.
Determination of Rh-CO Integrated Absorption Coefficients as a Function of Temperature and Coverage for ZSM-5 Supported Rhodium, M.S./BYU, April 1998. Advisor: Hecker
1997
Catalyst Characterization by Quantitative FTIR: Determination of Rh-CO Extinction Coefficients for Rh/ZMS-5
Hickenlooper, J.L. and Hecker, W.C.
Environmental Catalysis II, (in press), 1997. Also presented at the AIChE Annual Meeting, Los Angeles, California, November 17, 1997. Funded in part by ACERC.
The application of quantitative FTIR to heterogeneous catalysis allows the determination of surface concentrations of active intermediates. Successful application of quantitative FTIR depends upon understanding the factors affecting integrated extinction coefficients. Extinction coefficients relate integrated IR absorbance to surface concentration. Research on catalyst systems with 1% Rh has determined the Rh-CO extinction coefficients are not dependent upon oxide support, using the following supports: SiO2, Al2O3, Ce/SiO2, Ce/Al2O3, TiO2, and MgO. In addition, varying temperatures between 50° and 200°C and varying weight loadings from 0.2% to 9% appeared to have no effect on the extinction coefficients for Rh/SiO2 catalysts. Similar studies are being carried out on Rh/ASM-5. The following band frequencies have been observed on 0.8% Rh/AMS-5 catalyst: 2181 and 2150 cm^-1, 2100 (sh) and 2020 (sh) cm^-1, 2114, and 2048 cm^-1, 2117 and 2083 cm^-1 and 2069 cm^-1. The two weak bands at 2181 and 2150 cm^-1 are assigned to Rh (III)-CO where CO is bonded reversibly to the Rh(III) ion (Shannon et al. 1984). The bands at 2100 (sh) and 2020 (sh) cm^-1, 2114, and 2048 cm^-1, 2117 and 2083 cm^-1 are assigned to three types of RH(I) carbonyls (Shannon et al. 1984). The band at 2069 cm^-1 is proposed to be a linear Rh-CO species. Extinction coefficients for these Rh-Co species are being determined by combining peak areas from IR placed in a high temperature transmission reactor cell. The effects of temperature on the extinction coefficients for CO chemisorbed on Rh/ZMS-5 are also being determined. The results of this study will allow catalysis researched to apply quantitative FTIR to better understand catalytic surface reaction or Rh/ZMS-5 as well as demonstrate the use of an analytical system for determining extinction coefficients.