The development of green processes for the direct synthesis of H2O2 from H-2 and O-2 is of environmental and commercial importance. Basic understanding toward the high activity and selectivity of the PdAu bimetallic catalysts will be helpful for its further improvement. In this mini review main results in our previous studies are discussed and summarized. A mechanistic explanation for the origin of the high activity and selectivity achieved on the PdAu catalysts is put forward on the basis of that the effect of the co-adsorbed H atoms on the PdAu surface is taken into account. The role of the catalyst in the direct H2O2 synthesis might be just to supply active H atoms, by cleaving H-2 molecule, as the feedstock for the hydrogenation of O-2. It is shown from our DFT calculations that on the PdAu bimetallic catalyst the high activity of Pd and the high selectivity of Au are balanced and then high overall performance is accomplished for the synthesis of H2O2. (C) 2014 Elsevier B.V. All rights reserved.