The performances of Ni-Co/Al2O3 catalysts with the optimum composition were much higher than the corresponding monometallic Ni and Co catalysts in terms of the catalytic activity, the resistance to coke formation and catalyst life in the steam reforming of biomass tar. This behavior can be related to the formation of the Ni-Co solid solution alloys indicated from the characterization with XRD, TPR, TEM, H-2 adsorption and EXAFS. (C) 2012 Elsevier Ltd. All rights reserved.