Cs promoted Ni/ZrO2-Al2O3 catalysts for dry reforming of methane: Promotional effects of Cs for enhanced catalytic activity and stability

Abstract

Carbon Capture and Utilization (CCU) technologies offer a promising avenue for transforming captured CO2 into valuable products, serving as renewable fuels or precursors for high-value synthesis. This study explores the dry reforming of methane (DRM) as a viable pathway to convert captured CO2 and CH4 into syngas, achieving high equilibrium conversion through the use of suitable catalysts. Conventional nickel-based catalysts are susceptible to carbon deposition, necessitating innovative approaches to enhance their performance. A tubular microreactor was employed to conduct the reforming process at 800 °C, utilizing Cs-promoted Ni catalysts supported on 90 % Al2O3 and 10 % ZrO2-based support composition. Catalyst preparation involved the impregnation technique, and subsequent characterization employed N2-physisorption, XRD, H2-TPR, TGA, TPD, and Raman spectroscopy. The DRM reaction was systematically investigated using the Ni/ ZrO2- Al2O3 catalysts, with a specific focus on the catalytic effects of Cs promotion. Observations revealed that Cs incorporation onto the ZrO2- Al2O3 matrix led to a substantial increase in hydrogen yield and selectivity across all catalyst compositions, accompanied by a significant reduction in carbon deposition on the catalyst surface. The optimal Cs loading, determined to be 3 wt% over Ni/ ZrO2- Al2O3 catalyst, exhibited CO2 and CH4 conversions of 90 % and 87 %, respectively, with an H2/CO yield approaching 1 (0.95). This research underscores the potential of Cs-modified catalysts in enhancing the efficiency of DRM for CCU applications, providing valuable insights into optimizing catalyst formulations for improved performance in carbon transformation processes.