MCM-41 supported nickel-based bimetallic catalysts with superior stability during carbon dioxide reforming of methane: Effect of strong metal-support interaction

Nickel-based bimetallic catalysts supported on MCM-41 mesoporous molecular sieves (Ni-Ti-, Ni-Mn-, and Ni-Zr-MCM-41) were prepared by direct hydrothermal synthesis. The catalytic properties were tested in methane reforming with CO₂. All Zr-promoted catalysts exhibited comparable or enhanced initial catalytic activity as compared to Ni-MCM-41. Adding Zr⁴⁺ remarkably improved the long-term stability, whereas decreased lower initial activity and stability were observed for Ti- and Mn-modified catalysts. The addition of Zr⁴⁺ enhanced the structural stability and the dispersion of active Ni sites. The strong anchoring effect of Zr⁴⁺ and the partial activation of CO₂ by Zr⁴⁺ contributed to the high catalytic activity and long-term stability. On the contrary, the decoration of Ni clusters with TiO_x and MnO_x species on Ni-Ti and Ni-Mn catalysts hindered the accessibility of Ni-active centers, thus decreasing their catalytic performance. The partial transformation of amorphous silica matrix into quartz and/or tridymite phases over Ni-Mn, Ni-Ti, and Ni-MCM-41 catalysts also played a negative role on their catalytic stability.