Synthesis of Coke‐Resistant Catalyst Using NiAl2O4 Support for Hydrogen Production via Autothermal Dry Reforming of Methane

A highly porous NiAl2O4 spinel structure was synthesized and employed as a support for catalysts in the autothermal dry reforming of methane (ATDRM) in a monolithic‐type reactor. A series of catalyst with various metal species, X/NiAl2O4@monolith (X: Ni, Co, Pt, Rh, and Ru), was prepared. NiAl2O4 support provides a high dispersion of active metal species with a uniform size distribution, due to its high surface area, and large pore volume. These features enable catalysts to maximize catalytic performance by improving the adsorption and reaction rates of reactants. More notably, the use of NiAl2O4 support enhanced catalyst longevity by retarding coke formation during the ATDRM, due to its improved catalyst acidity compared to conventional alumina support. The conversion of feeed, CH4 and CO2 on X/NiAl2O4 catalysts increases in the order of Rh > Ni > Ru > Co > Pt. Notably, the inexpensive Ni catalyst exhibits slightly lower but comparable CH4 conversion to the expensive noble metal Rh when using NiAl2O4 as a supporting material: 93.7% for Ni vs. 95.2% for Rh. Moreover, applying monolithic reactors considerably increased methane conversion compared with fixed bed reactors due to the better distribution of active metal, increased activity per unit volume, high mass/heat transfer.