The Role of the Interface in CO Oxidation on Au/CeO₂ Multilayer Nanotowers

Abstract The CO oxidation reaction is studied in this work using a controlled structure consisting of Au/CeO₂ multilayers, in the form of towers of 10 × 10 µm² base, with layer thicknesses in the nanometer range. This structure is prepared on a 3″ Si wafer using reverse photolithography and vapor deposition in an e‐beam chamber. The thickness of each layer is of nanometer dimensions and only the edges of the Au and CeO₂ layers are exposed to the reaction gas mixture. The CO oxidation reaction rate is found to scale with the total length of the Au/CeO₂ interfaces for nanotowers with the same total Au and CeO₂ surface areas. TEM and X‐ray diffraction (XRD) analyses reveal highly stressed gold films in the nanotowers, the lattice strain being temperature and film thickness dependent. Deactivation with time‐on‐stream is commensurate with relaxation of the gold films, as measured by a drop in their lattice strain.