fig5

Figure 5. Mechanism studies. (A) X-ray photoelectron spectra of MnO_x/CeO₂(0.05), acid-treated MnO_x/CeO₂(0.05) and CeO₂. (B) Reaction rate and product selectivities in ethylbenzene oxidation over various catalysts. The triangles and stars represent the selectivities to 1-phenylethanol and acetophenone, respectively. (C) In-situ FTIR spectra of ethylbenzene adsorbed on MnO_x/CeO₂(0.05) at 25 and 160 °C in flowing Ar and then switched to O₂. (D) In-situ FTIR spectra of ethylbenzene adsorbed on H₂-reduced MnO_x/CeO₂(0.05) at 25 °C, O₂-regenerated MnO_x/CeO₂(0.05) at 25 °C and 80 °C. FTIR: Fourier transform infrared.