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Electrochemical sensing is an excellent analytical means with multiple applications. Most of the electrochemical developments are based on the novel electrochemically active substrates. A lot of them have been adopted from other fields of material science. Every new class of functional materials has impacted on the development of electroanalytical chemistry. In this view, lanthanide cuprates, a well recognized high temperature superconducting materials were considered for adrenaline sensing. Obtained from corresponding oxides, a highly crystalline La2CuO4 found to be a suitable substrate for analytical method development. It inherited sponge-like morphology common for the most of the previously reported lanthanum cuprates with narrow pore size distribution at 400–700 nm. Excellent charge mobility and low resistivity provided a carbon paste electrode with improved linearity range and low limit of detection. Repeatability and stability of the developed sensor were at satisfactory level. Sensor functionality was verified on the real samples with excellent recovery rates. With this work we suggest further development of electroanalytical methods with application of lanthanide cuprates.

Metabolism of metals in microalgae and adaptation to metal excess are of significant environmental importance. We report a three-step mechanism that the green microalga Chlorella sorokiniana activates during the acquisition of and adaptation to manganese (Mn), which is both an essential trace metal and a pollutant of waters. In the early stage, Mn2+ was mainly bound to membrane phospholipids and phosphates in released mucilage. The outer cell wall was reorganized and lipids were accumulated, with a relative increase in lipid saturation. Intracellular redox settings were rapidly altered in the presence of Mn excess, with increased production of reactive oxygen species that resulted in lipid peroxidation and a decrease in the concentration of thiols. In the later stage, Mn2+ was chelated by polyphosphates and accumulated in the cells. The structure of the inner cell wall was modified and the redox milieu established a new balance. Polyphosphates serve as a transient Mn2+ storage ligand, as proposed previously. In the final stage, Mn was stored in multivalent Mn clusters that resemble the structure of the tetramanganese–calcium core of the oxygen-evolving complex. The present findings elucidate the bioinorganic chemistry and metabolism of Mn in microalgae, and may shed new light on water-splitting Mn clusters.

The combination of an intense absorption of visible light and p-type semiconducting nature makes spinel cobalt oxide (Co3O4) a very attractive material for various optoelectronic applications. However, the traditional methods for its synthesis have been either time- and energy-consuming or relying on toxic chemicals. To solve this issue, a simple, facile, and eco-friendly method of synthesis was successfully developed to obtain spinel Co3O4 nanoparticles. The novel method for obtaining pure and monophasic Co3O4 reported here is based on the thermal decomposition of hexaaquacobalt(II) D-camphor10-sulfonate at 900 °C. This fast solid-state synthesis route overcomes the disadvantages of many combustion methods, most critically by avoiding the use of toxic organic solvents. The synthesized material was subjected to a detailed characterization to assess its potential for use as a nanocatalyst. The band gap measurements indicated the presence of two band gaps, one at 2.10 eV and another at 1.22 eV, confirming the purity and semiconducting properties of the sample. The electrochemical studies demonstrated a significant enhancement in the electron transfer kinetics with the addition of the synthesized Co3O4 to the carbon-paste electrode, leading to an enhanced electrocatalytic performance. These prominent functional properties, suitable for a wide range of technological applications, pave way for the implementation of the reported method for the synthesis of Co3O4 on a larger industrial scale.

The following investigation presents the thermal treatment of geopolymer at 300 °C, 600 °C and 900 °C. We investigated what happens to the geopolymer base when incorporated with 1% and 5% of neodymium in the form Nd2O3. A total of six samples were synthesized. Geopolymer 1 contained 1% and geopolymer 2 contained 5% Nd2O3, and these samples were treated at 300 °C; then, samples geopolymer 3 and geopolymer 4 also had the same percentage composition of Nd2O3 and were treated at 600 °C, while samples geopolymer 5 and geopolymer 6were treated at 900 °C. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers; however, with increased temperatures, these materials show even more unusual properties. Diffuse reflectance infrared Fourier transform (DRIFT) analysis showed that the intensity of the vibrational band decreases with the increase in temperature during thermal treatment, suggesting alterations in the chemical structure of the geopolymers. Transmission electron microscopy (TEM) analysis showed that the diameter of the nanoparticles containing Al2O3 is in the range 5–10 nm, while larger crystallites range from 30 to 80 nm. Scanning electron microscopy (SEM) analysis revealed that the temperature of the thermal treatment increases to 300 °C and 600 °C; the porosity of geopolymer increases in the form of the appearance of large pores and cracks in material. X-ray photoelectron spectroscopy (XPS) analysis was used to investigate the surface chemistry of geopolymers, including the chemical composition of the surface, the oxidation state of the elements, and the presence of functional groups. The UV/Vis spectra of the synthesized geopolymers doped with Nd3+ show interesting optical properties at 900 °C; the geopolymer matrix completely disintegrates and an amorphous phase with a rare-earth precipitate app

We have set-up an electrochemical advanced oxidation process for ethidium bromide (1), based on the Eu-doped MnWO4 (Eu:MnWO4), obtained through a template-driven synthesis, along with developing a suitable monitoring method. Under galvanostatic conditions, Eu:MnWO4-coated graphite electrode serves as anode, applicable for removal of 1. To go further and augment the catalytic method, we have applied a modified carbon paste electrode for the monitoring of 1 with the limit of detection (LOD) of 54 nM. Enhancement of the hydrogen evolution reaction is an indication of electrocatalytic properties of the material, whereby developed method emerges as a candidate for straightforward application in electrochemical advanced oxidation processes (EAOPs). We have enriched experimental data with theoretical insights, provided by Density Functional Theory (DFT), and proposed oxidation mechanism of 1. Based on obtained results, we propose the new nanomaterial as a potent electrochemical modifier, suitable for catalytic treatment and process monitoring of the 1-polluted waters.