Strontium-Promoted Ni/SiO2–ZrO2 Catalysts for Methane Dry Reforming: Unraveling the Role of Basicity, Metal–Support Interaction, and Coke Resistance

Abstract

The dry reforming of methane (DRM) using carbon dioxide mitigates greenhouse gases and produces synthesis gas, which is a valuable feedstock for various chemicals. The promoters are utilized to modify the intrinsic properties of Ni-based catalysts, which contribute to their better activity during DRM. The Ni-based catalysts supported over mixed support (5SiO₂–ZrO₂), denoted as SZ0, promoted with 1 to 4 wt % Sr (SZ1 to SZ4), were investigated for their catalytic performance during DRM. The catalysts are characterized by X-ray diffraction study, surface area and porosity, H₂-temperature-programmed reduction, CO₂-temperature-programmed desorption, Raman spectroscopy, and thermogravimetry. This work highlights the role of the Sr promoter in influencing catalytic activity by modifying the crystallinity, basicity, reducibility, and metal–support interaction. The metal support interaction improves with 1–4 wt % Sr addition, whereas the number of active sites grows by 2–4 wt % Sr addition. CH₄ conversion of 52.2% for SZ0 reached 66.8% for SZ3. The deactivation factor of 28.1% for SZ0 was reduced to 8.9% with the incorporation of 3 wt % Sr (SZ3). Despite the highest number of active sites and relatively stronger metal–support interaction, the catalytic activity over a 4 wt % Sr-promoted 5Ni/5SiO₂–ZrO₂ catalyst is limited due to the maximum deposit of graphitic carbon.