Controllable deposition of dispersed Pd nanoparticles on ZnO for Suzuki-Miyaura cross-coupling reactions.

Palladium nanoparticles find extensive applications in catalysis in both homogeneously and heterogeneously catalyzed processes. Supporting metal nanoparticles enhances their stability as compared to their unsupported counterparts. The role of catalytic support is increasingly recognized as crucial in determining the behaviour of these materials. However, controlling the deposition and anchoring of palladium nanoparticles remains a significant challenge. This contribution discusses the preparation of straight lines of palladium particles on zinc oxide by wet impregnation. This phenomenon is attributed to the highly stepped morphology of the employed ZnO that created steric anchoring sites to stabilize the metal particles. Palladium-based catalysts were evaluated for the valuable Suzuki-Miyaura cross-coupling reaction. The dispersed Pd/ZnO catalyst achieved a conversion rate of 86% with 100% selectivity, remarkably superior to that of the Pd/Al2O3 and Pd/TiO2 counterparts.

Using the Aqueous Phase Produced from Hydrothermal Carbonization Process of Brown Seaweed to Improve the Growth of Phaseolus vulgaris.

Seaweeds are considered a biomass for third-generation biofuel, and hydrothermal carbonization (HTC) is a valuable process for efficiently disposing of the excess of macroalgae biomass for conversion into multiple value-added products. However, the HTC process produces a liquid phase to be disposed of. The present study aims to investigate the effects of seed-priming treatment with three HTC-discarded liquid phases (namely AHL180, AHL240, and AHL300), obtained from different experimental procedures, on seed germination and plant growth and productivity of Phaseolus vulgaris L. To disentangle the osmotic effects from the use of AHL, isotonic solutions of polyethylene glycol (PEG) 6000 have also been tested. Seed germination was not affected by AHL seed-priming treatment. In contrast, PEG-treated samples showed significantly lower seed germination success. AHL-treated samples showed changes in plant biomass: higher shoot biomass was recorded especially in AHL180 samples. Conversely, AHL240 and AHL300 samples showed higher root biomass. The higher plant biomass values recorded in AHL-treated samples were the consequence of higher values of photosynthesis rate and water use efficiency, which, in turn, were related to higher stomatal density. Recorded data strongly support the hypothesis of the AHL solution reuse in agriculture in the framework of resource management and circular green economy.

On the Electroanalytical Detection of Zn Ions by a Novel Schiff Base Ligand-SPCE Sensor.

A novel bidentate Schiff base (L) is here proposed for the detection of Zn ions in water. The structure of the synthesized Schiff base L was characterized by FT-IR, 1H NMR and 13C NMR. Optical characteristics were addressed by UV-Visible spectroscopy and Photoluminescence (PL) measurements. PL demonstrated that L displays a "turn-off" type fluorescence quenching in the presence of Zn2+ ion in aqueous solution, indicating its ability to preferentially coordinate this ion. Based on these findings, an L-M (where M is a suitable membrane) modified screen-printed carbon electrode (SPCE) was developed to evaluate the electrochemical behavior of the Schiff base (L) with the final objective of undertaking the electroanalytical determination of Zn ions in water. Using various electrochemical techniques, the modified L-M/SPCE sensor demonstrates high sensitivity and selectivity to Zn ions over some common interferents ions, such as Ca2+, Mg2+, K+, Ni++ and Cd++. The potentiometric response of the L-M/SPCE sensor to Zn ions was found to be linear over a relatively wide concentration range from 1 µM to 100 mM.

Graphene Quantum Dots by Eco-Friendly Green Synthesis for Electrochemical Sensing: Recent Advances and Future Perspectives.

The continuous decrease in the availability of fossil resources, along with an evident energy crisis, and the growing environmental impact due to their use, has pushed scientific research towards the development of innovative strategies and green routes for the use of renewable resources, not only in the field of energy production but also for the production of novel advanced materials and platform molecules for the modern chemical industry. A new class of promising carbon nanomaterials, especially graphene quantum dots (GQDs), due to their exceptional chemical-physical features, have been studied in many applications, such as biosensors, solar cells, electrochemical devices, optical sensors, and rechargeable batteries. Therefore, this review focuses on recent results in GQDs synthesis by green, easy, and low-cost synthetic processes from eco-friendly raw materials and biomass-waste. Significant advances in recent years on promising recent applications in the field of electrochemical sensors, have also been discussed. Finally, challenges and future perspectives with possible research directions in the topic are briefly summarized.