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

Abstract

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.