In this research, we report a simple hydrothermal synthesis to prepare rhenium (Re)- doped MoS₂ flower-like microspheres and the tuning of their structural, electronic, and electrocatalytic properties by modulating the insertion of Re. The obtained compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Structural, morphological, and chemical analyses confirmed the synthesis of poorly crystalline Re-doped MoS₂ flower-like microspheres composed of few stacked layers. They exhibit enhanced hydrogen evolution reaction (HER) performance with low overpotential of 210 mV at current density of 10 mA/cm², with a small Tafel slope of 78 mV/dec. The enhanced catalytic HER performance can be ascribed to activation of MoS₂ basal planes and by reduction in charge transfer resistance during HER upon doping.

This work shows a sustainable methodology for the synthesis of biogenic materials designed for the removal and photodegradation of rhodamine B (RhB), a highly dangerous environmental pollutant that induces reproductive toxicity. The classical synthesis of MCM-41-ordered mesoporous materials was modified using biocompatible rice husk as the silica template. Iron was incorporated and the so-prepared biogenic photocatalysts were characterized by X-ray diffraction, N₂ adsorption–desorption isotherms, transmission electron microscopy, diffuse reflectance UV-Vis, surface pH, cyclic voltammetry, and Fourier transform infrared spectral analysis of pyridine adsorption. The photocatalytic performance of the materials was evaluated following the removal by adsorption and the photon-driven degradation of RhB. The adsorption capacity and photocatalytic activity of the biogenic materials were correlated with their properties, including iron content, texture, surface content, and electrochemical properties. The best biogenic material boosted the degradation rates of RhB under UV irradiation up to 4.7 and 2.2 times greater than the direct photolysis and the benchmark semiconductor TiO₂-P25. It can be concluded that the use of rice husks for the synthesis of biogenic Fe-modified mesoporous materials is a promising strategy for wastewater treatment applications, particularly in the removal of highly toxic organic dyes.

The foraging behavior of the infective juveniles (IJs) of entomopathogenic nematodes (EPNs) relies on host-derived compounds, but in a tri-trophic context, herbivore-induced root volatiles act as signals enhancing the biological control of insect pests by recruiting EPNs. In southern Chile, the EPN Steinernema australe exhibits the potential to control the raspberry weevil, Aegorhinus superciliosus, a key pest of blueberry Vaccinium corymbosum. However, there is no information on the quality of the blueberry root volatile plume or the S. australe response to these chemicals as putative attractants. Here, we describe the root volatile profile of blueberries and the chemotaxis behavior of S. australe towards the volatiles identified from Vaccinium corymbosum roots, infested or uninfested with A. superciliosus larvae. Among others, we found linalool, α-terpineol, limonene, eucalyptol, 2-carene, 1-nonine, 10-undecyn-1-ol, and methyl salicylate in root volatiles and, depending on the level of the emissions, they were selected for bioassays. In the dose–response tests, S. australe was attracted to all five tested concentrations of methyl salicylate, 1-nonine, α-terpineol, and 2-carene, as well as to 100 µg mL⁻¹ of 10-undecyn-1-ol, 0.1 and 100 µg mL⁻¹ of linalool, and 100 µg mL⁻¹ of limonene, whereas eucalyptol elicited no attraction or repellency. These results suggest that some volatiles released from damaged roots attract S. australe and may have implications for the biocontrol of subterranean pests.

Multiwalled carbon nanotube-glassy carbon electrodes (MWCNT-GCEs) were prepared and used to immobilize 5-nitroquinoline (5-NQ), 6-nitroquinoline (6-NQ) and 8-nitroquinoline (8-NQ). Cyclic voltammetry was used to study the conventional voltammetric behavior of these NQs dissolved in an aqueous alcoholic solution and compare them with the unconventional voltammetric behavior observed when the NQs were immobilized in a porous layer of MWCNTs. Increased currents and shift to lower overpotential can be explained by the change of the mass transport regime from semi-infinite diffusion to thin layer diffusion. Reduction peak potentials depended on the position of the nitro group (-NO₂) in the quinoline structure and the test cell pH. Reduction peak potential of -NO₂ was dependent on the mesomeric effect of the resonant structures and the inductive effect of the N heteroatom. ArNO/ArNHOH redox couple was electrogenerated in situ and immobilized on a nanostructured electrode network for all the studied NQs. The redox couple generated from 5-NQ was the most stable with 50% remaining at the 15th cycle. Even though the current intensity observed for 6-NQ was the largest, the stability of 6-NQ was 35% at the same voltammetric cycle. The lowest stability was observed for 8-NQ with only 25% remaining at the 15th cycle.