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The link between morphology and properties is well-established in the nanoparticle literature. In this report, we show that different approaches in the synthesis of copper oxide can lead to nanoparticles (NPs) of different size and morphology. The structure and properties of the synthesized NPs are investigated with powder X-ray diffraction, scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS). Through detailed SEM analyses, we were able to correlate the synthetic pathways with the particles' shape and aggregation, pointing out that bare hydrothermal pathways yield mainly spheroidal dandelion-like aggregates, whereas, if surfactants are added, the growth of the nanostructures along a preferential direction is promoted. The effect of the morphology on the electronic properties was evaluated through DRS, which allowed us to obtain the electron bandgap in every system synthesized, and to find that the rearrangement of threaded particles into more compact structures leads to a reduction in the energy difference. The latter result was compared with Density Functional Theory (DFT) computational models of small centrosymmetric CuO clusters, cut from the tenorite crystal structure. The computed UV-Vis absorption spectra obtained from the clusters are in good agreement with experimental findings.

In the quest to find powerful modifiers of screen-printed electrodes for sensing applications, a set of rare earth-doped Ca 10-x RE x (PO 4 ) 6 (OH) 2 (RE = La, Nd, Sm, Eu, Dy, and Tm and x = 0.01, 0.02, 0.10, and 0.20) hydroxyapatite (HAp) samples were subjected to an in-depth electrochemical characterization using electrochemical impedance spectroscopy and cyclic and square wave voltammetry. Among all of these, the inorganic phosphates doped with lanthanum proved to be the most reliable, revealing robust analytical performances in terms of sensitivity, repeatability, reproducibility, and reusability, hence paving the way for their exploitation in sensing applications. Structural data on La-doped HAp samples were also provided by using different techniques, including optical microscopy, X-ray diffraction, Rietveld refinement from X-ray data, Fourier transform infrared, and Raman vibrational spectroscopies, to complement the electrochemical characterization.

Extrinsic chemiluminescence can be an efficient tool for determining pesticides and fungicides, which do not possess any intrinsic fluorescent signal. On this basis, (3-aminopropyl) trimethoxysilane (APTMS)-coated ZnO (APTMS@ZnO) was synthesized and tested as an extrinsic probe for the fungicide penconazole. Several synthetic routes were probed using either a one-pot or two-steps method, in order to ensure both a green synthetic pathway and a good signal variation for the penconazole concentration. The synthesized samples were characterized using X-ray diffraction (XRD), infrared (IR), Raman and ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM) imaging and associated energy-dispersive X-ray (EDX) analysis. The average size of the synthesized ZnO nanoparticles (NPs) is 54 ± 10 nm, in line with previous preparations. Of all the samples, those synthesized in two steps, at temperatures ranging from room temperature (RT) to a maximum of 40 °C, using water solvent (G-APTMG@ZnO), appeared to be composed of nanoparticles, homogeneously coated with APTMS. Chemiluminescence tests of G-APTMG@ZnO, in the penconazole concentration range 0.7-1.7 ppm resulted in a quenching of the native signal between 6% and 19% with a good linear response, thus indicating a green pathway for detecting the contaminant. The estimated detection limit (LOD) is 0.1 ± 0.01 ppm.

Gold nanoparticles (AuNPs) were functionalized by ruthenium porphyrins through a sulfur/gold covalent bond using a three-steps reaction. The catalyst was characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) in order to control the binding of ruthenium porphyrin on AuNPs' surface. The catalyst was tested and compared with an analog system not bound to AuNPs in the oligomerization reaction using 1-phenylacetylene as the substrate.

In the present paper, we investigate the effects of alkali and operational temperature on NiO capacitive and optical properties. The NiO samples were prepared by a straightforward, surfactant-free hydrothermal synthesis, employing Ni(NO 3 ) 2 and either urea or moderately sterically hindered triethylamine (TEA). The syntheses were followed by calcinations at either 400 or 600 °C. NiO samples were characterized by XRD, scanning electron microscopy, and nitrogen adsorption isotherms. The optical properties were investigated by reflectance spectroscopy, and the pseudocapacitance was studied by cyclic voltammetry and galvanostatic charge charge-discharge measurements. We found that the synthesis with TEA yielded nanoflowers whereas the morphology of the synthesis with urea varied with the calcination temperature and resulted in nanoparticles or nanoslices at calcination temperatures of 400 and 600 °C, respectively. The NiO samples prepared at a lower temperature displayed a favorable combination of surface area and porosity that allowed for high performance with capacitances of 502 and 520 F g -1 at a current density of 1 A g -1 for nanoflowers and nanoparticles, respectively. The band gaps of all the samples were compatible with the estimated nanoparticle sizes. Finally, we used the synthesized NiO samples for the preparation of screen-printed electrodes (SPEs) modified by drop-casting and probed them against a [Fe(CN) 6 ] 3-/4- probe.

The synthesis of organic-inorganic hybrid compounds based on phenylphosphonate and their use as precursors to form LiMn x Fe (1-x) PO₄ composites containing carbonaceous substances with sub-micrometric morphology are presented. The experimental procedure includes the preliminary synthesis of Fe 2+ and/or Mn 2+ phenylphosphonates with the general formula Fe (1-x) Mn x [(C₆H₅PO₃)(H₂O)] (with 0 < x < 1), which are then mixed at different molar ratios with lithium carbonate. In this way the carbon, obtained from in situ partial oxidation of the precursor organic part, coats the LiMn x Fe (1-x) PO₄ particles. After a structural and morphological characterization, the electrochemical behavior of lithium iron manganese phosphates has been compared to the one of pristine LiFePO₄ and LiMnPO₄, in order to evaluate the doping influence on the material., Competing Interests: The authors declare no conflict of interest.