Subcritical water gasification of lignocellulosic wastes for hydrogen production with Co modified Ni/Al2O3 catalysts

Nickel-based catalysts with different supports and cobalt loadings were synthesized for hydrothermal gasification of cellulose at 350 degrees C. The activity of Ni catalysts was found in the order of Al2O3 > spent bleaching clay ash > SiO2 with H-2 yield of 80.6%, 69.0% and 57.0%. When 6 wt. % Co was added, 10Ni-6Co/Al2O3 showed the highest H-2 yield of 88.4% i.e., 1.44 times that without Co addition. Catalysts were characterized by NH3-TPD, TPR, XRD, BET and XPS, showing that Ni-Co alloy formation promoted H-2 production. Single-factor experiments were conducted to study variables in the presence of 10Ni-6Co/Al2O3 with the selected conditions of 0.5 g biomass and 20 min at 350 degrees C (achieving 94.9% H-2 yield from cellulose) for gasification of rice straw, peanut shell and cotton straw with the increase in H-2 yield by 51.4, 76.0 and 67.8 times. Ni-Co/Al2O3 catalysts enhanced hydrothermal gasification of actual agricultural residues. (C) 2020 Elsevier B.V. All rights reserved.