The effect of stepwise sulfidation on a MoO3/CeO2 Al2O3 catalyst for sulfur-resistant methanation was studied. The prepared catalysts were characterized using I\12-physisorption (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), and temperature-programmed sulfidation (TPS). The methanation activities and stability of the one-step-sulfided MoO3/CeO2 Al2O3 catalysts were enhanced by stepwise sulfidation processes. The XRD, TEM, RS, and XPS results indicated that the enhancement in the stability of MoO3/CeO2 Al2O3 was caused by the reduction and sulfidation of the CeO2 particles, eliminating unstable CeO2 and driving the migration of Ce-3* and Al3+ ions. The catalyst subjected to stepwise sulfidation exhibited improved methanation activity because the stepwise sulfidation reduced the degree of CeO2 sulfidation and mitigated textural structure damage to the catalyst. Finally, a sulfidation mechanism for CeO2 and MoO3 was proposed. (C) 2013 Elsevier B.V. All rights reserved.