One-Pot Synthesis of Functionalised rGO/AgNPs Hybrids as Pigments for Highly Conductive Printing Inks.

This work provides a method for the development of conductive water-based printing inks for gravure, flexography and screen-printing incorporating commercial resins that are already used in the printing industry. The development of the respective conductive materials/pigments is based on the simultaneous (in one step) reduction of silver salts and graphene oxide in the presence of 2,5-diaminobenzenesulfonic acid that is used for the first time as the common in-situ reducing agent for these two reactions. The presence of aminophenylsulfonic derivatives is essential for the reduction procedure and in parallel leads to the enrichment of the graphene surface with aminophenylsulfonic groups that provide a high hydrophilicity to the final materials/pigments.

Spark Discharge Aerosol-Generated Copper-Based Nanoparticles: Structural & Optical Properties; Application on the Antiviral (SARS-CoV-2) and Antibacterial Improvement of Face Masks.

Nanoparticle formation by Spark Discharge Aerosol Generation offers low-cost fabrication of nanoparticles, without the use of chemicals or vacuum. It produces aerosol particles of a few nanometers in size with high purity. In this work, copper-based -CuO (tenorite) and Cu- nanoparticles are produced, characterized and used to modify face mask air filters, achieving the introduction of antibacterial and antiviral properties. A range of characterization techniques have been employed, down to the atomic level. The majority of the particles are CuO (of a few nanometers in size that agglomerate to form aggregates), the remainder being a small number of larger Cu particles. The particles were deposited on various substrates, mainly fiber filters in order to study them and use them as biocidal agents. On face masks, their antibacterial activity against Escherichia coli (E.coli) results in a 100 % decrease in bacteria cell viability. Their antiviral activity on face masks results in a 90 % reduction of the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) viability, 15 minutes post the application of the virus stock solution. This highlights the effectiveness of this approach, its simplicity, its low cost and its excellent environmental credentials.

Photocatalysis as an advanced reduction process (ARP): The reduction of 4-nitrophenol using titania nanotubes-ferrite nanocomposites.

TiO2 photocatalysis is an advanced process, employed worldwide for the oxidation of organic compounds, that leads to significant technological applications in the fields of health and environment. The use of the photocatalytic approach in reduction reactions seems very promising and can open new horizons for green chemistry synthesis. For this purpose, titanium dioxide nanotubes (TNTs) were developed in autoclave conditions using TiO2 P25 as a precursor material. Based on these nanotubular substrates, TiO2/CoFe2O4 (TCF) nanocomposites were further obtained by wet impregnation method. The materials were thoroughly characterized and their structural, textural, vibrational, optoelectronic and magnetic properties were determined. The composite materials combine absorbance in the visible optical range and high BET surface area values (˜100 m2/g), showing extremely high yield in the photocatalytic reduction of 4-nitrophenol (4-NP), exceeding 94% within short illumination time (only 35 min). The developed nanocomposites were successfully reused in consecutive photocatalytic experiments and were easily removed from the reaction medium using magnets. Both remarkable recycling ability and high-performance stability in the photocatalytic reduction of nitrophenol were observed, thus justifying the significant economic potential and industrial perspectives for this advanced reduction process.

Trimethylsulfonium Lead Triiodide: An Air-Stable Hybrid Halide Perovskite.

We report on the synthesis, characterization, and optoelectronic properties of the novel trimethylsulfonium lead triiodide perovskite, (CH3)3SPbI3. At room temperature, the air-stable compound adopts a hexagonal crystal structure with a 1D network of face-sharing [PbI6] octahedra along the c axis. UV-vis reflectance spectroscopy on a pressed pellet revealed a band gap of 3.1 eV, in agreement with first-principles calculations, which show a small separation between direct and indirect band gaps. Electrical resistivity measurements on single crystals indicated that the compound behaves as a semiconductor. According to multi-temperature single-crystal X-ray diffraction, synchrotron powder X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry, two fully reversible structural phase transitions occur at -5 and ca. -100 °C with reduction of the unit cell symmetry to monoclinic as temperature decreases. The role of the trimethylsulfonium cation regarding the chemical stability and optoelectronic properties of the new compound is discussed in comparison with APbI3 (A = Cs, methylammonium, and formamidinium cation), which are most commonly used in perovskite solar cells.