In this work, we report the preparation of TiO₂ nanoparticles with a high surface area, from 120 to 168 m² g⁻¹ by the hydrothermal-microemulsion route and hydrothermal temperature effect over particle size, porosity, and photovoltaic parameter. The TiO₂ samples were characterized by Raman, BET, TEM, SEM-FE, I–V curves, and EIS. The increase of hydrothermal temperature correlates with particle and pore size. Although when the synthesis temperature was 250 °C, the surface area presents an unexpected decrease of c.a. 28%. TiO₂ samples were employed as thin-film photo-anodes for dye-sensitized solar cell (DSSC) solar cells. Photovoltaic results showed that the sample prepared at 250 °C presented the more suitable textural properties for the DSSC application. The prepared TiO₂ materials with a particle size of 6.93 ± 0.59 nm and anatase crystalline phase favor electron transport and diffusion of electrolyte species, which directly impact in solar cell efficiency.

In the present work, chemically modified graphene oxide (GO) was incorporated as a crosslinking agent into thin-film composite (TFC) nanofiltration (NF) membranes for water desalination applications, which were prepared by the interfacial polymerization (IP) method, where the monomers were piperazine (PIP) and trimesoyl chloride (TMC). GO was functionalized with monomer-containing groups to promote covalent interactions with the polymeric film. The composite GO/polyamide (PA) was prepared by incorporating amine and acyl chloride groups into the structure of GO and then adding these chemical modified nanomaterial during IP. The effect of functionalized GO on membrane properties and performance was investigated. Chemical composition and surface morphology of the prepared GO and membranes were analyzed by thermogravimetric analysis (TGA), Raman spectroscopy, FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The fabricated composite membranes exhibited a significant increase in permeance (from 1.12 to 1.93 L m⁻² h⁻¹ bar⁻¹) and salt rejection for Na₂SO₄ (from 95.9 to 98.9%) and NaCl (from 46.2 to 61.7%) at 2000 ppm, when compared to non-modified membranes. The amine- and acyl chloride-functionalized GO showed improved dispersibility in the respective phase.