(455d) Fabrication of Nano-Structured Catalyst Supports by ALD

Interactions between a transition-metal catalyst and its support can strongly alter the stability and activity of the catalyst. Important examples include support effects with ceria and the so-called “Intelligent Catalysts” in which the metal can be redispersed by reversible ex-solution from a perovskite lattice. However, the surface areas of these functional supports are often too low or unstable; and, in the case of perovskites, the length scales for ingress and egress may be too long to take advantage of the effect. We are addressing these issues by depositing very thin films of various functional oxides, ~0.5 to 1 nm thick, onto high-surface-area supports, including Al₂O₃ and MgAl₂O₄, by Atomic Layer Deposition. We have demonstrated that a wide range of oxides, including mixed oxides with the perovskite structure, can be deposited as dense, uniform films on various supports. The films exhibit surprisingly good thermal stability and provide catalytic properties similar to that observed with bulk oxides, but with higher surface areas. The thin-film catalysts also simply structural and thermodynamic characterization of the catalyst-support interactions.