In this work, iron hexacyanoferrate (FeHCF—Prussian blue) particles have been grown onto a reduced graphene oxide substrate through a pulsed electrodeposition process. Thus, the prepared FeHCF electrode exhibits a specific volumetric capacitance of 88 F cm⁻³ (specific areal capacitance of 26.6 mF cm⁻²) and high cycling stability with a capacitance retention of 93.7% over 10,000 galvanostatic charge–discharge cycles in a 1 M KCl electrolyte. Furthermore, two identical FeHCF electrodes were paired up in order to construct a symmetrical supercapacitor, which delivers a wide potential window of 2 V in a 1 M KCl electrolyte and demonstrates a large energy density of 27.5 mWh cm⁻³ at a high power density of 330 W cm⁻³.

Determining the texture distribution of permanent magnets is very useful since this information allows us to relate the macroscopic properties with the microstructural characteristics of the magnet through a statistical average. Usually, this distribution is determined by x-ray diffraction (θ–2θ, rocking curve, pole figures) or electron backscatter diffraction. However, for manufacturing process control purposes, these techniques are not necessarily appropriate because those analyses are relatively time-consuming and require sophisticated equipment, and the analyzed volume of the sample is not statistically representative of the magnet. In this context, this paper presents a route based on magnetometry, which, together with an appropriate mathematical approach, turns out to be an advantageous methodology, capable to provide statistically reliable information, faster, and with less sophisticated laboratory infrastructure.

Graphene based composites and blends are potential candidates for fast and highly dense energy storage devices such as supercapacitors. Here is reported the preparation of highly corrugated graphene (CG) thin films onto plastic sheets of polyvinyl chloride (PVC) through thermal treatment using hydroiodic acid (HI) as the reducing agent. These films can be used as electrode materials for supercapacitors without the need for binders or metal current collectors. The films show a specific gravimetric capacitance of 170 F g⁻¹ at 0.125 A g⁻¹ and retains over 81% of their initial capacitance after 10 000 repeating cycles of charging/discharging. When the CG film is prepared in the presence of polyaniline (PANI), the resultant composite electrode (CG–PANI) presents a high specific gravimetric capacitance of 1041 F g⁻¹, over 6 times greater than CG electrodes. Further, a symmetrical solid-state supercapacitor with CG–PANI electrodes is assembled by using a polyvinyl alcohol/sulfuric acid (PVA/H₂SO₄) gel electrolyte that shows an impressive volumetric energy density of 3.1 mW h cm⁻³ while maintaining a volumetric power density of 73.9 mW cm⁻³. This simple and costless effective preparation method of CG and its polyaniline composite can open up exciting opportunities for supercapacitor applications.

P-type and n-type metal oxide semiconductors are widely used in the manufacture of gas sensing materials, due to their excellent electronic, electrical and electrocatalytic properties. Hematite ( α -Fe ₂ O ₃ ) compound has been reported as a promising material for sensing broad types of gases, due to its affordability, good stability and semiconducting properties. In the present work, the efficient and easy-to-implement sol-gel method has been used to synthesize α -Fe ₂ O ₃ nanoparticles (NPs). The TGA-DSC characterizations of the precursor gel provided information about the phase transformation temperature and the mass percentage of the hematite NPs. X-ray diffraction, transmission electron microscopy and x-ray photoelectron spectroscopy data analyses indicated the formation of two iron oxide phases (hematite and magnetite) when the NPs are subjected to thermal treatment at 400 °C. Meanwhile, only the hematite phase was determined for thermal annealing above 500 °C up to 800 °C. Besides, the crystallite size shows an increasing trend with the thermal annealing and no defined morphology. A clear reduction of surface defects, associated with oxygen vacancies was also evidenced when the annealing temperature was increased, resulting in changes on the electrical properties of hematite NPs. Resistive gas-sensing tests were carried out using hematite NPs + glycerin paste, to detect quaternary ammonium compounds. Room-temperature high sensitivity values ( S _r ∼ 4) have been obtained during the detection of ∼1 mM quaternary ammonium compounds vapor. The dependence of the sensitivity on the particle size, the mass ratio of NPs with respect to the organic ligand, changes in the dielectric properties, and the electrical conduction mechanism of gas sensing was discussed.

We have studied the influence of the organic molecule DL-Dithiothreitol on the properties of isotropic conductive adhesives for application in microelectronics. The Ag fillers were prepared from commercial micro flakes or submicron particles from waste jewelry. The results show that coating of the Ag recycled fillers with thiol avoided the agglomeration of the particles improving the dispersion and the electrical and mechanical properties. By comparing the samples, the better properties were obtained from adhesives with recycled Ag particles relative to the ones formulated with commercial Ag flakes and improvement can be attributed to the absence of the lubricant layer and smaller size of the particles produced from recycled silver.