Effect of nano-support and type of active metal on reforming of CH₄ with CO₂

Two series of Co and Ni based catalysts supported over commercial (ZrO₂, CeO₂, and Al₂O₃) nano supports were investigated for dry reforming of methane. The catalytic activity of both Co and Ni based catalysts were assessed at different reaction temperatures ranging from 500 - 800 °C; however, for stability the time on stream experiments were conducted at 700 °C for 6 h. Various techniques such as N₂ adsorption-desorption isotherm, temperature-programmed reduction (H₂-TPR), temperature-programmed desorption (CO₂-TPD), temperature-programmed oxidation (TPO), X-ray diffraction (XRD), thermogravimetric analysis (TGA) were applied for characterization of fresh and spent catalysts. The catalytic activity and stability tests clearly showed that the performance of catalyst is strongly dependent on type of active metal and support. Furthermore, active metal particle size and Lewis basicity are key factors which have significant influence on catalytic performance. The results indicated that Ni supported over nano ZrO₂ exhibited highest activity among all tested catalysts due to its unique properties including thermal stability and reducibility. The minimum carbon deposition and thus relatively stable performance was observed in case of Co-Al catalyst, since this catalyst has shown highest Lewis basicity. The resistance towards carbon deposition is significantly influenced by active metal particle size of Ni/Co and Lewis basicity of the prepared catalyst. On the other hand activity and stability have a strong relation with nature of nano support and type of active metal (i.e., Ni/Co) used.