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The selective oxidation of methane into methane oxygenates such as CH3OH and HCOOH with O2 is a promising technology for direct methane conversion. This study successfully demonstrates the partial oxidation of methane over Pd−Fe/ZSM‐5 catalysts in water, where H2O2 was generated in situ from H2 and O2. A low Pd content is essential for preventing agglomeration of Pd nanoparticles, and intimate contact between Pd and Fe species is beneficial for achieving high yields of methane oxygenates. This one‐body catalyst showed better catalytic performance than that of previously reported ones, especially at low temperatures. 0.28 %Pd–0.56 %Fe/ZSM‐5 exhibited a stable catalytic performance in a continuous flow reactor. [ABSTRACT FROM AUTHOR]

The selective oxidation of methane into methane oxygenates such as CH3OH and HCOOH with O2 is a promising technology for direct methane conversion. This study successfully demonstrates the partial oxidation of methane over Pd−Fe/ZSM‐5 catalysts in water, where H2O2 was generated in situ from H2 and O2. A low Pd content is essential for preventing agglomeration of Pd nanoparticles, and intimate contact between Pd and Fe species is beneficial for achieving high yields of methane oxygenates. This one‐body catalyst showed better catalytic performance than that of previously reported ones, especially at low temperatures. 0.28 %Pd–0.56 %Fe/ZSM‐5 exhibited a stable catalytic performance in a continuous flow reactor. [ABSTRACT FROM AUTHOR]

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 H2, 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 1H-NMR. The homogeneous Cu species increase hydrogen peroxide decomposition and CO2 selectivity, which is undesirable for this reaction. [ABSTRACT FROM AUTHOR]