Robust stability of La- and Ce- dual-promoted Ni/ZrO2 catalyst for CO2 methanation

The sintering issue of Ni nanoparticles seriously limits the practical application of the Ni-based catalysts for CO2 methanation. This work demonstrates that the La- and Ce- dual-promoted Ni/ZrO2 shows better durability at 600 ºC and 60000 ml gcat-1 h-1 over 200 h compared with the La- or Ce- single-promoted. The composition and microstructure characterization indicates that the dispersion and sintering resistance of Ni nanoparticles is enhanced with the dual-promoted catalysts. Both depth profile of X-ray photoelectron spectroscopy and density functional theory calculation show that in the La- and Ce- dual-promoted Ni/ZrO2, the reduced dissolution of Ce into ZrO2 lattice and the spread of La on ZrO2 surface by forming a La2O3-CeO2 solid solution improves the dispersion and stability of Ni nanoparticles. This work provides a facile strategy to mitigate the sintering of Ni nanoparticles and thus improve the stability of Ni-based catalysts for CO2 methanation.