Reaction mechanisms on Rhodium (Rh)

1) Surface reactions: Catalytic partial oxidation of methane on rhodium

Version: 1.0 (February 13, 2001)
Evaluation: evaluated on steady state experimental measurements of species profiles in short-contact-time reactor using honeycomb monoliths (Rh/Al2O3) at CH4/O2 = 1.4 – 2.3 and temperatures 800 – 1300K. 3D – Flow field simulation is coupled with detailed surface kinetics including thermal wall conductivity.
Reference: O. Deutschmann, R. Schwiedernoch, L.I. Maier, D. Chatterjee. Natural Gas Conversion VI, Studies in Surface Science and Catalysis 136, E. Iglesia, J.J. Spivey, T.H. Fleisch (eds.), p. 215-258, Elsevier, 2001 Version: 1.1 (2003)
Evaluation: evaluated on the transient light-off measurements of CH4/O2 mixtures in short-contact-time flow reactor (residence time 20 ms) using honeycomb monoliths (Rh/Al2O3) at the temperature range 385 – 1000K.
Reference: R. Schwiedernoch, S. Tischer, C. Correa, O. Deutschmann. Chem. Eng. Sci. 58 (2003), 633-642

2) Surface reactions: combined steam reforming and catalytic partial oxidation of methane on rhodium

Version: 2.0 (2009)
Evaluation: evaluated by comparison between calculated and experimentally determined conversion, selectivity, and species concentrations in a microchannel reactor at ambient pressure, temperature 673 – 973K, steam to carbon ratio (S/C) = 3 -8 by variation of the residence time inside the microchannels between 38 and 220 ms. Furthermore, the model is evaluated at supplemental feeding of products (H2, CO, CO2).
Reference: J. Thormann, L. Maier, P. Pfeifer, U. Kunz, K. Schubert, O. Deutschmann. International J. Hydrogen Energy 34 (2009), 5108-5120

3) Surface reactions: Three-way catalytic converter ( Pt/Rh )

Version:1.0 (2001)
Evaluation: the mechanism was validated on steady state experiments in flow reactor with commercial Pt/Rh coated three-way catalytic converter. Experimentally measured species (CO, NO, C3H6) profiles at nearly stoichiometric (λox=0.9), rich (λox=0.5), and lean (λox=1.8) conditions (T = 400- 900K) were compared with 2D Fluent simulation coupled with detailed surface kinetics.
Reference: D. Chatterjee, O. Deutschmann, J. Warnatz. Faraday Discussions 119 (2001) 371-384.

4) Surface reactions: Catalytic partial oxidation of iso-octane and propane over an alumina coated honeycomb monolith (Rh)

Version: 1.0 (2010)
Evaluation: evaluated by comparison between simulated and experimentally measured product composition in a flow reactor with Rh/Al2O3 monolith catalyst by variation of inlet temperatures and C/O ratio 0.8 - 2.0, residence time 40 ms.
Reference: M. Hartmann, L. Maier, O. Deutschmann. Catalytic Partial Oxidation of Iso-Octane over Rhodium Catalysts: An Experimental, Modeling, and Simulation Study. Combustion and Flame, 157 (2010) 1771-1782

5) Surface reactions: Steam reforming of hexadecane over a Rh/CeO2 catalyst in microchannel reactor

Version: 1.0 (2009)
Evaluation: evaluated by comparison between calculated and experimentally determined conversion, selectivity , and species concentrations in a microchannel reactor at ambient pressure, temperature 673 - 973K, steam to carbon ratio (S/C) = 3 -8 by variation of the residence time inside the microchannels between 38 and 220 ms. Furthermore, the model is evaluated at supplemental feeding of products (H2, CO, CO2).
Reference: J. Thormann, L. Maier, P. Pfeifer, U. Kunz, K. Schubert, O. Deutschmann. International J. Hydrogen Energy 34 (2009), 5108-5120

6) Surface reactions: Catalytic oxidation of hydrogen over rhodium

Version: 1.1 (2012)
Evaluation: evaluated on steady-state experimental measurements in stagnation-point reactor over Rh/Al2O3 catalyst at 673 -873K; experimentally determined catalytic ignition temperatures for stagnation point flows of H2/O2mixtures; experimentally measured species profiles in annular flow reactor (320 – 970K). Surface kinetics is thermodynamically consistent for a temperature range 273 – 1273K.
Reference: C. Karakaya, O. Deutschmann, Kinetics of Hydrogen Oxidation on Rh/Al2O3 Catalysts Studied in a Stagnation-flow Reactor, Chemical Engineering Science, 89 (2012) 171-184.

7) Surface reactions: Catalytic oxidation of carbon monoxide over rhodium

Version:1.1 (2013)
Evaluation: evaluated by comparison between simulations and steady-state experiments in stagnation-point reactor over Rh/Al2O3 catalyst at 521 - 873K; light-off measurements of CO/O2mixtures in continuous-flow reactor (300 – 525K). Surface kinetics is thermodynamically consistent for a temperature range 273 – 1273K
Reference: H. Karadeniz, C. Karakaya, S. Tischer, O. Deutschmann, Numerical Modeling of Stagnation-flows on Porous Catalytic Surfaces: CO Oxidation on Rh/Al2O3, Chemical Engineering Science, 117(2014)136

8) Surface reactions: Catalytic water-gas shift (WGS) reaction over rhodium

Version:1.1 (2014)
Evaluation: evaluated on steady-state experimental measurements for water-gas shift (WGS)-, reverse water-gas shift (R-WGS) reaction and preferential oxidation of CO in stagnation flow reactor over Rh/Al2O3 catalyst at 873 - 1073K; experimentally measured species profiles in continuous flow reactor (473 – 1173K) with technical Rh/γ-Al2O3 monolith catalyst. Surface kinetics is thermodynamically consistent for a temperature range 273 – 1273K.
Reference:C. Karakaya, R. Otterstätter, L. Maier, O. Deutschmann, Kinetics of the water-gas shift reaction over Rh/Al2O3 catalyst, Appl. Catal. A: Gen. 470 (2014) 31- 44.

9) Surface reactions: Catalytic oxidation and steam/dry reforming of methane over rhodium

Version:2.0 (2015)
Evaluation: evaluated on steady-state experiments for partial oxidation, steam- and dry reforming of methane in stagnation flow reactor over Rh/Al2O3 catalyst at 298 - 1173K, 100 – 1100 mbar; comparison with experimentally measured species profiles in annular flow reactor (573 – 1123K) and spatial profile measurements along the foam structured Rh/Al2O3 monolith catalyst. Surface kinetics is thermodynamically consistent for a temperature range 273 – 1273K.
Reference:C. Karakaya, L. Maier, O. Deutschmann, Surface Reaction Kinetics for Oxidation and Reforming of CH4 over Rh/2O3 catalyst, International Journal of Chemical Kinetics, Vol. 48(3) (2016) pp. 144 - 160.

Catalyst

Fuel on Surface

Gasphase kinetics