The indiscriminate use of naproxen as an anti-inflammatory has been the leading cause of pollution in sewage effluents. Conversely, titanium dioxide is one of the most promising photocatalyst for the degradation of pollutants. Ti-La mixed oxides containing 0, 1, 3, 5, and 10 wt.% of lanthanum were synthetized by sol-gel and tested as photocatalysts in the degradation of naproxen (NPX). The materials were further characterized by X-ray diffraction (XRD), nitrogen physisorption (BET), scanning electron microscopy (SEM), UV-Vis and Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The XRD patterns resembled that of anatase titania. The Eg values, determined from the UV-Vis spectra, vary from 2.07 to 3.2 eV corresponded to pure titania. The photocatalytic activity of these materials showed a degradation of naproxen from 93.6 to 99.8 wt.% after 4 h under UV irradiation.

Nanostructured films with electrical conductivity in the semiconductor region were prepared in a polymeric matrix of poly(vinyl alcohol) (PVA) with nanostructures of chitosan-gold nanoparticles (AuNPs)/single-wall carbon nanotubes carboxylic acid functionalized (SWCNT-COOH) (chitosan-AuNPs/SWCNT-COOH) self-assembled. Dispersion light scattering (DLS) was used to determine the average particle sizes of chitosan-AuNPs, z-average particle size (Dz) and number average particle size (Dn), and the formation of crystalline domains of AuNPs was demonstrated by X-ray diffraction (XRD) patterns and observed by means of transmission electron microscopy (TEM). The electrostatic interaction was verified by Fourier transform infrared spectroscopy (FTIR). The electrical conductivity of PVA/chitosan-AuNPs/SWCNT-COOH was determined by the four-point technique and photocurrent. The calculated Dn values of the chitosan-AuNPs decreased as the concentration of gold (III) chloride trihydrate (HAuCl₄·3H₂O) increased: the concentrations of 0.4 and 1.3 mM were 209 and 90 nm, respectively. Average crystal size (L) and number average size (D) of the AuNPs were calculated in the range of 13 to 24 nm. Electrical conductivity of PVA/chitosan-AuNPs/SWCNT-COOH films was 3.7 × 10⁻⁵ σ/cm determined by the four-point technique and 6.5 × 10⁻⁴ σ/cm by photocurrent for the SWCNT-COOH concentration of 0.5 wt.% and HAuCl₄·3H₂O concentration of 0.4 mM. In this investigation, the protonation of the amine group of chitosan is fundamental to prepare PVA films with nanostructures of self-assembled chitosan-AuNPs/SWCNT-COOH.

In this work, a layered double hydroxide support modified with cadmium was synthesized by a one-pot coprecipitation method. Then, it was sulfured in different percentages by a solvothermal method. Next, the samples were analyzed using various characterization techniques like XRD, DRS, FTIR, N₂ physisorption, PL spectroscopy, TEM, and SEM. Finally, the synthesized and uncalcined materials were assessed in hydrogen production from water and a methanol-water solution under UV-light irradiation. The results showed that the sulphuration improves the photocatalytic activity, reaching a maximum rate constant of hydrogen production of 7403 µmol/g∙h in a methanol-water solution and 1326 µmol/g∙h in water.