Hydrogen and methane selectivity during alkaline supercritical water gasification of biomass with ruthenium-alumina catalyst

► Ru/Al2O3 catalyst was effective in the gasification of biomass with CGE of more than 96% for glucose. ► Ru/Al2O3 and alkaline additives e.g. CaO gave higher selectivities towards H2 and CH4 production. ► With sodium formate and acetate, Ru/Al2O3 gave gas products rich in both methane and hydrogen gas. ► Results indicated that Ru/Al2O3 could catalyze the reversible Sabatier reaction for H2 and/or CH4.