The loss of ZnO as the support for metal catalysts by H2 reduction

The reduction of ZnO in the ZnO-supported catalyst to metallic zinc, the alloying of metallic zinc with the second metal and the evaporation of zinc species during the reductive atmosphere of hydrogen was investigated in this study. The results show that the reduction temperature was the determining factor for the transformation of zinc species. The complete removal of ZnO in ZnO-supported catalyst can be achieved at 700℃. The effects of different metals supported on ZnO on the transformation of ZnO were also investigated. Cu, Co and Ni species can slow the ZnO loss due to the priority for the reduction of these metal oxides and the formation of metal-Zn intermetallics. Fe based catalyst noticeably accelerated the loss of ZnO which can be ascribed to the high oxophilicity of Fe and the strong interactions between metal and support.