Gallic acid (GA), a polyphenol extensively used in the food, wine, and pharmaceutical industries, is known for its inhibitory effects on soil microbial activity. Photocatalytic degradation offers an environmentally friendly solution for GA removal from water. In this work, graphitic carbon nitride (g-C₃N₄) photocatalysts were synthesized by two methods: thermal exfoliation (CN-E) and supramolecular assembly via hydrothermal processing (HCN-II). Structural analyses by XRD, FTIR, and XPS confirmed the formation of the g-C₃N₄ framework, while SEM revealed that CN-E consisted of folded and curled nanosheets, whereas HCN-II displayed a polyhedral–nanosheet hybrid architecture with internal channels. Both materials achieved approximately 80% GA degradation within 180 min under visible-light irradiation, yet HCN-II exhibited a superior apparent rate constant (k = 0.01156 min⁻¹) compared with CN-E. Radical trapping experiments demonstrated that O₂•⁻ and h⁺ were the primary reactive oxygen species involved, with OH• making a minor contribution. The enhanced performance of HCN-II is attributed to its higher surface area, improved light harvesting, and efficient charge separation derived from supramolecular assembly. These findings highlight the potential of engineered g-C₃N₄ nanostructures as efficient, metal-free photocatalysts for the degradation of recalcitrant organic pollutants in water treatment applications.

Alternative methodologies to analyze and quantify surface morphology using techniques such as Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) are of great interest to researchers. This study presents an approach using fractal dimension (D) analysis to characterize FeCrAl alloy plates oxidized in an air atmosphere at 750, 800, 850, and 900 °C for 24 h. SEM and AFM surface traces were used to determine the fractal dimensions via Rescaled Range (R\S) analysis using the BENOIT program; with this, it is expected that the fractal dimension results are between 1 ≤ D ≤ 2. The fractal dimension analysis describes with precision the surface morphology, given that local topographic features are represented by the analyzed traces. The experimental results demonstrate that D increases with the oxidation temperature for both techniques, which correlated with an increase in surface roughness. Specifically, SEM results in D values of 1.402, 1.545, 1.557 and 1.583, while AFM results in values of 1.494, 1.561, 1.573 and 1.593 at respective temperatures. Fractal dimension analysis is a robust tool for quantifying micro- and nanostructured roughness. This approach allows researchers to track surface changes induced by thermal, mechanical, or environmental processes, thus transforming SEM into a quantitative complementary technique.

In this work the production of poly(3-hexylthiophene) (P3HT) by electropolymerization using different materials as working electrodes is reported. Initially, the tests were carried out under atmospheric conditions with all the electrodes, and subsequently those that showed the best performance were selected to repeat the experiments in an inert atmosphere. The formation of the polymer film on the electrode surface was characterized by Fourier transform infrared spectroscopy (FT-IR) in the mid-infrared region (4000–400 cm⁻¹). This technique allowed the evaluation of the transmittance of P3HT deposited on the electrode surface. The presence of the polymer was confirmed by the appearance of characteristic absorption bands at 2920 cm⁻¹, 2850 cm⁻¹, 850 cm⁻¹ and 730 cm⁻¹. The absorption peaks found at 2920 cm⁻¹, 2850 cm⁻¹ and 850 cm⁻¹ show the presence of the typical functional groups of P3HT. These results suggest that the proposed method could represent a viable alternative for obtaining semiconductor polymers, avoiding the use of initiators with free radicals potentially harmful to human health.

The release of methyl orange (MO) into bodies of water represents a serious environmental problem due to its chemical stability, toxicity, and persistence. To address this issue, this work presents the green synthesis of silver nanoparticles (AgNPs) using natural extracts of rose leaves (RL), rose petals of the pink Castile rose (PCR), and common yellow rose petals (YRP) as reducing agents. The formation of the AgNPs was confirmed by ultraviolet–visible (UV-Vis) spectroscopy through the localized surface plasmon resonance (LSPR) band and Transmission Electron Microscopy (TEM) obtaining sizes smaller than 15 nm, while FTIR analysis confirmed the presence of phenols, flavonoids, and proteins, which are suggested by spectral shifts to act as reducing and stabilizing agents. After optimizing the synthesis, the AgNPs were supported on gamma-alumina (γ-Al₂O₃). Gamma-alumina is characterized by a large surface area and high chemical and thermal stability; it inhibits nanoparticle agglomeration, thereby significantly improving electron-hole pair separation in photocatalytic processes, ultimately forming AgNPs/γ-Al₂O₃ photocatalysts. The activity of these composites was evaluated in the degradation of MO under UV irradiation (254 nm) and white light LED (380–750 nm). The catalysts demonstrated a dye removal trend, achieving degradation efficiencies under ultraviolet light of 4.94% (RL), 24.69% (YRP), and 60.49% (PCR); these figures increased under white LED light to 43.21% (RL), 64.20% (YRP), and 76.54% (PCR) after 60 min. It is hypothesized that this enhanced performance under visible light arises from mechanisms driven by reactive oxygen species (ROS) boosted by the LSPR effect, as has been documented in similar plasmonic systems. It is concluded that these supported photocatalysts constitute an environmentally friendly, sustainable, and alternative for wastewater treatment.