In the present work, catalytic activities of sewage sludge char supported Re-Ni bimetallic catalyst toward cracking/reforming of naphthalene and biomass tar were studied. Several proportions of Re and Ni (i.e. 1:9, 3:7, 5:5, 7:3 and 9:1) were investigated and their activities were compared to char, Ni/char and Re/char catalysts. Among all catalysts, the highest naphthalene cracking conversion and H-2 yield were achieved from Re-Ni/char with Re:Ni ratio of 3:7. From the post-reaction characterizations, the additional of Re into Ni not only improves the dispersion of Ni on char surface by preventing agglomeration of particles but also improve the catalyst resistance toward carbon deposition. The additional of steam and O-2 along with naphthalene as steam and autothermal reforming were also carried out. The presences of suitable steam and O-2 can further promote H-2 production and significantly reduce the degree of carbon formation. Under optimum conditions at 800 degrees C with H2O/C and O-2/C molar ratios of 1.5 and 0.3, the catalyst exhibited high biomass tar conversion with only 5% deactivation in H2 yield after 18 h operation. Therefore, this study indicates the successful development of catalyst and process for biomass tar conversion via cracking and reforming processes. (C) 2018 Elsevier Ltd. All rights reserved.