Enhanced Oxygen Mobility and Reactivity for Ethanol Steam Reforming

This article describes a strategy for increasing oxygen storage capacity (OSC) of ethanol steam reforming (ESR) catalysts. Sintering and carbon deposition are major defects of nickel-based catalysts for ESR; tuning oxygen mobility (OM) of CeO2-based supports can overcome these drawbacks and promote H-2 production. We have successfully increased OSC and OM by adding Mg into the lattice of Ni/CeO2 to promote H-2 production in ESR. The insertion of Mg into the CeO2 lattice efficiently promotes the reduction of Ce4+ according to X-ray powder diffraction (XRD) and temperature-programmed reduction (TPR) analysis. Mg-modified Ni/CeO2 catalysts have larger OSC and smaller nickel crystallite size compared with bare Ni/CeO2. The optimal Mg addition is 7 mol % (Ni/7MgCe) with the best OM. We also present evidence indicating that Mg addition significantly promotes ethanol conversion and H-2 production in ESR, and that Ni/7MgCe yields the best performance due to the high OM of the support. These Mg-modified catalysts also produce less carbon deposition compared with Ni/CeO2, and the amount of deposited carbon decreases with increasing Mg addition. Ni/7MgCe has the best resistance to carbon deposition owing to the excellent OM. (C) 2011 American Institute of Chemical Engineers AIChE J, 58: 516-525, 2012