Synthesis of PdO-ZnO mixed oxide precursors for PdZn intermetallic catalysts

PdZn mixed oxides are precursors for the formation of intermetallic PdZn phases, which show improved catalytic performance for methanol steam reforming. In this work we have prepared mixed oxides (PdxZn1-xO) that span a range of compositions around the tetragonal PdZn 1:1 L10 phase (x = 0.25, 0.5 and 0.75). We find that Pd+2 can be isomorphously substituted into hexagonal ZnO and likewise Zn+2 can also be substituted within tetragonal PdO. Our results show that the mixed oxide has a composition Pd0.75Zn0.25O within the tetragonal PdO lattice with a slight contraction in unit cell volume. The results are relevant for understanding the enhanced sensing properties of ZnO and the nature of the oxide precursors for the synthesis of intermetallic PdZn nanoparticles for heterogeneous catalysis.