A series of palladium catalysts supported on ordered mesoporous carbon (Pd/OMC-T) were prepared with a variation of preparation temperature (T = 8, 15, 25, 35, and 45 degrees C) of ordered mesoporous carbon (OMC). Conversion of hydrogen and yield for hydrogen peroxide over Pd/OMC-T catalysts showed volcano-shaped trends with respect of preparation temperature in the presence of halide and acid additives. The catalytic performance was found to be closely related to the palladium surface area. With an attempt not to use acid additive, another series of palladium catalysts supported on heteropolyacid (HPA)-containing ordered mesoporous carbon (Pd/OMC-XHPA) were prepared with a variation of HPA content (X = 5, I 0, 20, 30, and 40 wt%) using OMC-25 as a support. Selectivity and yield for hydrogen peroxide showed volcano-shaped trends with respect to HPA content, The superior catalytic performance of the catalyst at a certain HPA content (Pd/OMC-20HPA) was attributed to its high acidity caused by introduction of HPA into the pores of the catalyst. (C) 2016 Elsevier B.V. All rights reserved.