Use of structured systems as a strategy to minimize the deactivation of Ni-based catalysts applied in dry reforming of methane

Abstract

In this work, the Ni/γ-Al₂O₃ (Ni/Al) and Ni/La₂O₃-γ-Al₂O₃ (Ni/La-Al) catalysts were synthesized using the all-in-one method and applied to dry methane reforming, with the aim of minimizing the effects of deactivation through the use of La and the application of monoliths. The characterization showed a smaller Ni crystallite size for the catalyst promoted by La, which was associated with better dispersion of its active phase. The monoliths showed a conversion rate around 15% higher than that of the powdered catalysts. By studying the deactivation of the monoliths and applying residual activity deactivation models (DMRA), it was possible to verify a fit with R² greater than 0.90 and RMSE values below 5%, with the model predicted and adjusted to the residual activity region. In addition, the highest and lowest deactivation of the structured systems was identified for WHSV values of 40 and 20 L h⁻¹ g⁻¹_cat, respectively. Finally, the regeneration of the catalysts with CO₂ proved to be superior to that with H₂, with a regeneration rate of 90% in the first two cycles.