Controlled modification of nanoporous gold: Chemical vapor deposition of TiO2 in ultrahigh vacuum

TiO2 has been deposited in the first 400 nm of a nanoporous gold (NPG) structure using metal organic chemical vapor deposition with titanium-tetraisopropoxide as single source precursor in ultra high vacuum. The NPG has been pretreated by ozone to clean and stabilize the structure for deposition. The deposited oxide stabilizes the porous structure, otherwise prone to coarsening at elevated temperatures, up to 300 °C. The study combines the controlled sample preparation with a functional test of the prepared catalyst under real conditions in a continuous gas flow reactor. The catalytic activity of the loaded NPG at 60 °C for CO oxidation is found to be superior to unloaded as-prepared NPG.