In this study, less contaminated and porous SiO₂ films were grown via ALD at room temperature.

The catalytic activity of cobalt and iron nanoparticles for the growth of carbon nanotubes (CNTs) was studied by a specific reproducible and up-scalable fabrication method. Co and Fe catalysts were deposited over SiO₂ nanoparticles by a wet-impregnation method and two different annealing steps were applied for the catalyst formation/activation. The samples were calcined at an optimal temperature of 450 °C resulting in the formation of metal oxide nano-islands without the detection of silicates. Further reduction treatment (700 °C) under H₂ successfully converted oxide nanoparticles to Co and Fe metallic species. Furthermore, the catalytic efficiency of both supported-metal nanoparticles at 2 and 5% in weight of silica was evaluated through the growth of CNTs. The CNT structure, morphology and size dispersion were tailored according to the metal catalyst concentration.

The growth process of zinc oxide (ZnO) thin films by atomic layer deposition (ALD) accompanied by the presence of oxygen gas pulsing is investigated by means of the isotopic tracking of oxygen ¹⁸ O from the water precursor and oxygen ¹⁶ O from the gas.

The construction of a ZnO/SnO₂ heterostructure is considered in the literature as an efficient strategy to improve photocatalytic properties of ZnO due to an electron/hole delocalisation process. This study is dedicated to an investigation of the photocatalytic performance of ZnO/SnO₂ heterostructures directly synthesized in macroporous glass fibres membranes. Hydrothermal ZnO nanorods have been functionalized with SnO₂ using an atomic layer deposition (ALD) process. The coverage rate of SnO₂ on ZnO nanorods was precisely tailored by controlling the number of ALD cycles. We highlight here the tight control of the photocatalytic properties of the ZnO/SnO₂ structure according to the coverage rate of SnO₂ on the ZnO nanorods. We show that the highest degradation of methylene blue is obtained when a 40% coverage rate of SnO₂ is reached. Interestingly, we also demonstrate that a higher coverage rate leads to a full passivation of the photocatalyst. In addition, we highlight that 40% coverage rate of SnO₂ onto ZnO is sufficient for getting a protective layer, leading to a more stable photocatalyst in reuse.