Methanol Partial Oxidation Over Shaped Silver Nanoparticles Derived from Cubic and Octahedral Ag2O Nanocrystals

Ag-catalyzed methanol partial oxidation is an important industrial catalytic reaction. Herein we report the morphology effect of Ag catalysts on the catalytic activity in methanol partial oxidation. Shaped Ag nanoparticles were prepared by reducing the cubic and octahedral Ag2O nanocrystals under methanol vapor atmosphere. Ag nanoparticles were observed to undergo serious restructuring during methanol partial oxidation, but Ag nanoparticles derived from octahedral Ag2O nanocrystals were found to be more intrinsically active than those derived from cubic Ag2O nanocrystals. Ex situ characterizations demonstrated the more facile formation of active oxygen species on Ag nanoparticles derived from octahedral Ag2O nanocrystals than on Ag nanoparticles derived from cubic Ag2O nanocrystals. Therefore, although undergoing serious restructuring under the harsh reaction conditions of methanol partial oxidation, the original morphology of Ag nanoparticles exerts strong influences on the structure and catalytic activity of restructured Ag nanoparticles. These results demonstrate that strong correlations between original surface structure and restructured surface structure of catalyst nanoparticles even under very harsh reaction conditions and add fundamental understandings of methanol partial oxidation over Ag catalysts.