Carbon Domains on MoS₂/TiO₂ System via Catalytic Acetylene Oligomerization: Synthesis, Structure, and Surface...

Carbon domains have been obtained at the surface of a MoS₂/TiO₂ (Evonik, P25) system via oligomerization and cyclotrimerization reactions involved in the interaction of the photoactive material with acetylene. Firstly, MoS₂ nanosheets have been synthesized at the surface of TiO₂, via sulfidation of a molybdenum oxide precursor with H₂S (bottom-up method). Secondly, the morphology and the structure, the optical and the vibrational properties of the obtained materials, for each step of the synthesis procedure, have been investigated by microscopy and spectroscopy methods. In particular, transmission electron microscopy images provide a simple tool to highlight the effectiveness of the sulfidation process, thus showing 1L, 2L, and stacked MoS₂ nanosheets anchored to the surface of TiO₂ nanoparticles. Lastly, in-situ FTIR spectroscopy investigation gives insights into the nature of the oligomerized species, showing that the formation of both polyenic and aromatic systems can be taken into account, being their formation promoted by both Ti and Mo catalytic sites. This finding gives an opportunity for the assembly of extended polyenic, polyaromatic, or mixed domains firmly attached at the surface of photoactive materials. The presented approach, somehow different from the carbon adding or doping processes of TiO₂, is of potential interest for the advanced green chemistry and energy conversion/transport applications.