Di Stasi, C. Cortese, M. Greco, G. Renda, S. González, B. Palma, V. Manyà, J.J. Optimization of the operating conditions for steam reforming of slow pyrolysis oil over an activated biochar-supported Ni–Co catalyst Int. j. hydrogen energy 10.1016/j.ijhydene.2021.05.193 2021 2021