Hydrogen production by oxidative methanol reforming on Pd/ZnO: Catalyst preparation and supporting materials

Abstract

Pd and Pd–Zn alloy were supported on various supporting materials using impregnation, co-precipitation and microemulsion methods, and their catalytic performances in oxidative methanol reforming (OMR) were investigated. Pd/ZnO exhibited much higher selectivity than either Pd/Al 2O 3 or Pd/ZrO 2 in the OMR for hydrogen production. This was attributed to the presence of Pd–Zn alloy on the ZnO support. Elemental Pd on Al 2O 3 or ZrO 2 promotes methanol decomposition reaction and increases CO formation. Using a microemulsion method, a highly selective Pd/ZnO can be obtained with much lower Pd loading than that in samples prepared by co-precipitation. Modification of Al 2O 3 with ZnO produced a ZnAl 2O 4 phase, which was found to be a good support for the Pd/ZnO catalyst. Highly active and selective Pd/ZnO/ZnAl 2O 4 catalysts for the OMR reaction, containing much lower Pd loadings have been developed by impregnation of the supports with an aqueous solution of Pd(NO 3) 2 + Zn(NO 3) 2.