Partial oxidation of methane on NixAlBEA and NixSiBEA zeolite catalysts: Remarkable effect of preparation procedure and Ni content

• Two different C-NixSiBEA and C-NixAlBEA catalytic systems was obtained with varied physicochemical properties
• The crystal structure of both catalysts series was preserved even treatment at 750 °C
• The most active and stable catalysts in POM reaction were C-Ni5SiBEA and C-Ni10SiBEA
• The carbon deposit was not observed for both catalytic system
• The deactivation of C-NixAlBEA catalysts is probably related to sintering of Ni species

This work reports on the investigation of the influence of the preparation procedure and Ni content on partial oxidation of methane to synthesis gas. For this purpose the Ni-containing zeolite catalysts were prepared by two different methods: a conventional wet impregnation method (NixAlBEA series), in which Ni ions were introduced mainly in the extra framework position and a two-step postsynthesis method (NixSiBEA series), which allowed incorporating Ni ions into the zeolite framework. Calcined NixAlBEA and NixSiBEA zeolite catalysts showed different physicochemical properties and thermal stability in POM reaction. The C-NixSiBEA catalysts demonstrated very high activity (100% conversion of CH4) and selectivity to CO (up to 100%) and resistance to deactivation. Moreover, they were much more stable than C-NixAlBEA catalysts. On neither of 2 series of catalysts carbon deposition was observed in contrast to the catalysts usually used and described in literature. The TPR-H2 experiments showed the presence of different Ni species in C-NixSiBEA and C-NixAlBEA catalysts and XRD analysis proved that dealumination and high temperature treatment did not destroy the zeolite structure.

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