Mechanistic study in catalysis using dynamic and isotopic transient infrared spectroscopy: CO/H2C2H4 reaction on MnRh/SiO2

The Promoting Effect of Fe Doping on Rh/CeO2 for the Ethanol Synthesis

“…This indicated that the CO(l) band was more stable than in case of CO(gdc). Meanwhile, the position of CO(l) shifted to lower frequency, which can be due to the decreased dipole-dipole interaction [52]. Although the spectral features of the two catalysts are very similar, there are still some noticeable differences.…”

Mechanism of C2+ oxygenate synthesis on Rh catalysts

“…Similarities in the wavenumbers of the CO ligand of the metal complex and adsorbed CO as well as the oxophilic nature of the Lewis acid and Ce (or Mn, La, Fe) promoter has led to assignment of the low wavenumber CO to a tilted CO species in which CO binds to the Rh surface and the oxygen atom interacts with the oxophilic promoter as shown in figure 6. Although the addition of the oxophilic promoter led to the formation of tilted CO species as well as an enhancement of C 2 oxygenate formation [55], transient infrared studies revealed that tilted CO over Ce-and Mn-Rh/SiO 2 is inactive for CO insertion at 303 K [73,74]. Modeling of the isotopic transient response shows that the role of the Mn promoter is to increase the coverage of adsorbed CO, ethyl and acyl species, -thereby promoting the rate-limiting step, which enhancing the rate of propionaldehyde formation [75].…”

Mechanistic Investigation of Heterogeneous Catalysis by Transient Infrared Methods

“…Determination of the reactivity of adsorbates is of critical importance in developing an understanding of heterogeneous catalytic reaction mechanisms [1][2][3][4][5][6]. Although developments of various spectroscopic techniques have contributed to the identification of reaction intermediates that are responsible for certain elementary steps [1][2][3][7][8][9], elucidation of the overall reaction mechanism remains a key challenge in heterogeneous catalysis research.…”