Resumen:

The growth of nanowires (NWs) has become a well-established method, with numerous techniques used to synthesise hundreds of different NWs, the most common being chemical vapour deposition (CVD) via the vapour-liquid-solid (VLS) mechanism. In contrast, floating catalyst chemical vapour deposition (FCCVD) is a relatively new method for synthesising one-dimensional (1D) materials such as NWs and carbon nanotubes (CNTs), offering the unique advantage of ultra-fast growth directly from the gas phase. Despite its potential, successful FCCVD synthesis has been under-reported in the literature.
While the VLS growth of NWs has been extensively studied, significant gaps remain in terms of catalyst behaviour, thermodynamic predictions, NW polymorphism, and theoretical optimisation of growth condi- tions. In this first phase of my PhD, I will review the existing literature to identify these gaps and seek answers to key questions such as the appearance of soot, solid nanoparticles, catalyst enlargement, and the formation of NWs or CNTs in FCCVD.
The work will begin with an introduction to the basic concepts necessary to understand the study, including an explanation of NWs and a comparison between substrate-based CVD (SCVD) and FCCVD, highlighting the advantages of the latter, particularly in terms of higher growth rates. The role of the catalyst in the synthesis process and its critical importance are then explored.
A detailed discussion of the underlying phenomena in FCCVD, in particular the role of phase interfaces in controlling the synthesis, will be provided. Furthermore, we will theoretically explain the variety of products observed in FCCVD and the conditions under which they are formed.
Finally, the work will conclude by
outlining future research directions to be pursued during my PhD.