A new -Mn-Cu- mixture catalyst with components of 50.9 wt% CuMn2O4, 46.1 wt% CuO and 3.0 wt% Mn2O3 was made by a co-precipitation method firstly. We adopted the multi-component catalyst together with activated carbon (AC) and Na2CO3 (N) for the first time to conduct supercritical water partial oxidative gasification (SWPO) of sewage sludge at 450 degrees C, 25 MPa, 0.3 of oxidation coefficient and 5h of residence time, so as to improve H-2 production and organics removal. The results show that MnO2-AC-N, CuO-AC-N and -Mn-Cu-AC-N could obviously improve H-2 yield and removal efficiency of organics in sewage sludge SWPO. At -Mn-Cu-AC-N conditions, H-2 yield and X-COD (removal efficiency of chemical oxygen demand) were 202.4 mL/L and 95.6 wt%, much higher than 48.7 mL/L and 86.2 wt% obtained without catalyst, respectively. The -Mn-Cu-AC-N catalyst seemingly had the best catalytic effect on gas formation as well as on organics removal in sewage sludge SWPO among MnO2-AC-N, CuO-AC-N and -Mn-Cu-AC-N. Potential catalytic reaction pathways were proposed as well. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.