Аннотация:Supported gold nanoparticles are promising catalysts for new production of H2O2 from O2 and H2. Efficiency of a catalyst can be improved by changing size of nanoparticles and by adding palladium impurities. Investigation of H2O2 formation and dissociation mechanism on gold and mixed gold-palladium nanoparticles of different size is very important to create new type of efficient heterogeneous catalysts. For this purpose DFT/PBE approach with relativistic all electron basis set is used.
Aun and Aun-1Pd (n=2, 8, 20) have been chosen as a models of a catalysts. H2O2 formation (H+OOH=H2O2) and its dissociation (H2O2=HO+HO) have been considered. H2O2 synthesis on gold is hindered due to high Ea of H+OOH=H2O2, which increase with increase of gold cluster size. Palladium impurities promote H2O2 synthesis lowering corresponding Ea. Regardless to nanoperticle size H2O2 dissociation is more probable on bimetallic systems. Thus bimetallic catalyst is more active and less selective compared to gold catalyst.