Growth of an alumina overlayer deposited on a Au₁₀₁/TiO₂ model catalyst via atomic layer deposition

A major challenge in maintaining the unique, size-dependent properties of metal clusters arises from their tendency to agglomerate after deposition, which leads to the loss of their unique electronic and geometrical properties. To address this issue, coating the clusters with an overlayer of metal oxide has been proposed as an effective strategy for enhancing the metal cluster stability. Herein, several atomic layer deposition (ALD) cycles of AlO_x were applied in a high-vacuum chamber to a Au₁₀₁/TiO₂ model catalyst to investigate the growth and stability of the deposited overlayer. A combination of X-ray photoelectron spectroscopy, ion scattering spectroscopy in conjunction with sputtering, and neutral impact collision ion scattering spectroscopy was used to determine the composition and thickness of the ALD-AlO_x overlayer deposited onto the Au₁₀₁/TiO₂ sample. This study explores the potential benefits of utilizing ALD-AlO_x overlayers to maintain metal cluster properties.