High Performance and Stability of the Pt‐W/ZSM‐5 Catalyst for the Total Oxidation of Propane: The Role of Tungsten

Abstract

AbstractTungsten‐modified 1.5 wt. % platinum supported on ZSM‐5 catalysts were prepared, and their performances for the total oxidation of propane and the role of tungsten in the catalysts were investigated. The results show that the addition of tungsten can improve the catalytic activity of Pt/ZSM‐5. When the tungsten loading is 5 wt. %, the Pt‐5W/ZSM‐5 catalyst demonstrates excellent catalytic activity and its turnover frequency is more than 1 order of magnitude higher than that of the Pt/ZSM‐5 catalyst. Analyses of the surface properties of catalysts reveal that metallic platinum is scarcely found on the Pt/ZSM‐5 catalyst without tungsten; the addition of tungsten can modify the nature of platinum species, which results in the presence of metallic platinum in the Pt‐W/ZSM‐5 catalyst. The amount of metallic platinum in the Pt‐W/ZSM‐5 catalyst depends on the tungsten loading and can correlate directly with its catalytic activity. Therefore, the oxidation resistance of platinum in the Pt‐W/ZSM‐5 catalyst seems to be responsible for the improved catalytic activity in propane oxidation. In addition, the Pt‐5W/ZSM‐5 catalyst demonstrates higher stability; no deactivation of the Pt‐W/ZSM‐5 catalyst is observed after the online test for 50 h, with the temperature alternating between 200 °C for 10 h and 500 °C for 10 h. Therefore, the Pt‐5W/ZSM‐5 catalyst demonstrates better catalytic activity for propane oxidation than the Pt/ZSM‐5 catalyst after online aging at 700 °C for 30 h.