Effects of Cu Species on Liquid-Phase Partial Oxidation of Methane with H2O2 over Cu-Fe/ZSM-5 Catalysts

In this study, a Cu-promoted Fe/ZSM-5 catalyst was examined to reveal the effects of Cu species in selective oxidation of methane into methane oxygenates using H2O2 in water. Cu/ZSM-5, Cu-Fe/ZSM-5, and Fe/ZSM-5 catalysts were prepared using wet impregnation, solid-state ion exchange, and ion-exchange methods. Various techniques, including nitrogen physisorption, temperature-programmed reduction with H-2, UV-vis spectroscopy, and FT-IR spectroscopy after NO adsorption, were utilized to characterize the catalysts. The promotional effect of Cu on the Cu-Fe/ZSM-5 catalyst in terms of methanol selectivity was confirmed. The preparation method has a considerable influence on the catalyst performance, and the ion-exchange method is the most effective. However, leaching of the Cu species was observed during this reaction, which can affect the quantification of formic acid by H-1-NMR. The homogeneous Cu species increase hydrogen peroxide decomposition and CO2 selectivity, which is undesirable for this reaction.

Automated summary

In this study, the effects of Cu species in selective oxidation of methane into methane oxygenates using H2O2 in water were investigated. The Cu-promoted Fe/ZSM-5 catalyst showed enhanced methanol selectivity. The preparation method significantly influenced the catalyst performance, with the ion-exchange method being the most effective. However, leaching of Cu species was observed during the reaction, which could impact the quantification of formic acid.