Effect of substitution by Ni in MgAl2O4 spinel for biogas dry reforming

Mesoporous nanocrystalline Mg1-xNixAl2O4 (x = 0.10, 0.13, 0.17 and 0.20) with large surface area were synthesized via a simple one-step sol-gel method using nonprecious metals. The prepared Mg1-xNixAl2O4 catalysts exhibit good catalytic performance towards methane and carbon dioxide dry reforming reaction. The catalysts were evaluated by various techniques, including XRD, BET, TPR, TPO, EPR, Chemisorption, SEM and TEM. All the Ni incorporated MgAl2O4 samples possessed high BET area (296-305 m2 g−1) and pore volume (0.47-0.56 cm3 g−1) with small pore size (6.4-7.4 nm) in meso region after calcination at 700 °C. The TPR results suggested strong interaction effect in NiMg and the reducibility property of the catalysts improved with the increase of nickel doping. Mg0.8Ni0.2Al2O4 exhibited the highest activity for biogas dry reforming with 72.6% CH4 and 80.7% CO2 conversion at 700 °C. Electron paramagnetic resonance (EPR) results indicated that the incorporation of Ni in MgAl2O4 spinel lattice led to the lattice distortion and formed oxygen vacancies which are a benefit for the dry reforming reaction.