Promotional effect of Ce, Mg, Si, and Ti on Ni/Al2O3 catalysts for dry reforming of methane

Dry reforming of methane (DRM) has attracted increasing interest due to its ability to transform greenhouse gases, such as CH₄ and CO₂, into useful synthesis gas composed of H₂ and CO. Ni supported on Al₂O₃ is commonly applied in this reaction; however, its activity tends to decline due to sintering and carbon accumulation. This work evaluated how Ce, Mg, Si, and Ti promoters influence Ni/Al₂O₃, with the goal of improving its catalytic performance in DRM. Four different catalysts were synthesized using equal molar amounts of promoters, and their influence on Ni crystallite size, reduction properties, as well as surface basicity was investigated through various characterization techniques, such as X-ray diffraction, H₂-TPR, and CO₂-TPD analyses. Ni/Ce-Al exhibited the optimal performance in the DRM owing to its small Ni crystallite size, excellent reducibility, and superior CO₂ activation capability. Although the other promoted catalysts affected the physicochemical properties of Ni, they did not improve the DRM performance due to their lower reducibility, larger Ni particle size, and diminished CO₂ activation ability. This study highlights the promotional effects on Ni/Al₂O₃ catalysts and provides a pathway for the development of durable DRM catalysts.