Mechanism of Ce/La/Zr doping on the structure and anti-coking performance of Ni/MgO-MgAl2O4 catalyst
Dry reforming of methane (DRM) converts CH4 and CO2 into syngas, offering a route to mitigate greenhouse gases. Ni-based catalysts suffer from sintering and carbon deposition at high temperatures. This work employs MgO-MgAl2O4 composite supports to regulate Ni loading and introduces Ce, La, and Zr as promoters to investigate their effects on DRM activity, structural stability, and surface oxygen species. Optimal Ni loading of 12.5% yields highest CH4 and CO2 conversions. Promoter introduction slightly suppresses low-temperature activity but substantially modifies support local structure and metal-support interface, improving NiO dispersion and increasing surface oxygen vacancies and active oxygen species (Oβ). These changes enhance CO2 adsorption-activation and suppress carbon deposition. After 20 h DRM, Ce-promoted catalyst shows smallest Ni particle growth (6.23→8.07 nm) and lowest carbon deposition, demonstrating superior stability and anti-coking capability. The study elucidates how Ce, La, and Zr enhance sintering and coking resistance via interfacial electronic modulation and improved oxygen storage/release, guiding rational design of stable Ni-based DRM catalysts.