Enhanced catalytic activity of Ni–Mo₂C/La₂O₃–ZrO₂ bifunctional catalyst for dry reforming of methane

A series of Ni-modified Mo₂C catalysts with La₂O₃-stabilized ZrO₂ supports were synthesized via template method coupled with incipient wetness impregnation and temperature-programmed carbonization. The catalyst was tested in dry reforming of methane (DRM) reaction at the temperature range from 973 to 1173 K in a fixed-bed quartz reactor under atmospheric pressure. XRD, Raman, BET, H₂-TPD, SEM, EDS and TEM were conducted to characterize the phase constitution, the pore structure, the morphology and the crystal structure of the catalysts. Ni–Mo₂C nanoparticles of ~ 3 nm diameter were obtained for these catalysts, and the La₂O₃–ZrO₂ supports exhibited a cubic lattice structure with a sheet shape, which is believed to contain an abundant of oxygen vacancies. And the synergistic interaction between the oxygen vacancy in La–Zr–O solid solution and the Ni–Mo₂C particles could decrease the apparent activation energy of CO₂. Both of them are beneficial for accelerating DRM reaction. CH₄ conversion of the best specimen catalyst reaches 94% at 1173 K, and the catalyst maintains its stability after 100-h reaction. The superior catalytic activity of NMLZ-7.5 is attributed to the improved BET surface area (33.2 m²/g), smaller crystallites, grain boundaries and oxidation–carbonization cycle of Ni–Mo₂C.