Ni-Co bimetallic catalysts for the simultaneous production of carbon nanofibres and syngas through biogas decomposition

•Biogas for the co-production of filamentous-like materials and syngas is proposed.•NiCo bimetallic catalysts with different Ni/Co ratio are studied.•Catalytic performance is related to the type of carbon formed.•NiCo catalysts achieved high carbon nanofibre yield and catalyst stability.•This is related to a synergistic effect between Ni and Co.