Synthesis of Coke‐Resistant Catalyst Using NiAl<sub>2</sub>O<sub>4</sub> Support for Hydrogen Production via Autothermal Dry Reforming of Methane
Yasin Khani, Sumin Pyo, Farzad Bahadoran, Kanghee Cho, Kwang‐Eun Jeong, Young‐Kwon Park
Abstract
Abstract A highly porous NiAl 2 O 4 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 catalysts with various metal species, X/NiAl 2 O 4 @monolith (X: Ni, Co, Pt, Rh, and Ru), was prepared. NiAl 2 O 4 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 NiAl 2 O 4 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 feed, CH 4 and CO 2 on X/NiAl 2 O 4 catalysts increases in the order of Rh > Ni > Ru > Co > Pt. Notably, the inexpensive Ni catalyst exhibits slightly lower but comparable CH 4 conversion to the expensive noble metal Rh when using NiAl 2 O 4 as a supporting material: 93.7% for Ni versus 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, and high mass/heat transfer.