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CO2 accumulation is inducing an effect of global warming. Adsorption using solid sorbents is proving as an effective strategy for CO2 capture and reuse. The aim of this study was to develop amino-functionalized magnetic nanoparticles by depositing various amines through co-precipitation or impregnation-sonication. Structural characteristics were studied through SEM, BET and XRD analyses, evidencing coarse particles with low crystallinity and surface areas of 100–150 m2 g−1, while FT-IR confirmed CO2 interacting with substrate. The load of functional group, particles stability, and CO2 sorption capacity were assessed through elemental and thermogravimetric analysis. It was found that loads of functional groups ranging from 1.6 to 6.1 wt.%. were deposited, and most samples showed sound stability up to 100°C. Sorption capacities were in the range 0.2–1.5 g gNH2−1, the highest being 1.46 g gNH2−1 for ɛ-aminocaproic acid. Such sample also exhibited good recyclability, with a performance drop of 11% after many cycles. CO2 uptake decreased with increasing temperature in the range 25–45°C, suggesting a chemical bond between CO2 and amines. Amino functionalized particles could thus be an interesting solution for CO2 capture and utilization thanks to fast kinetics, recyclability, and ease of separation.

In the present study, the possibility of nickel deposition from a deep eutectic solvent on a water-sensitive substrate like aluminium was investigated. The electrolyte used was based on a 1:2 molar mixture of choline chloride and urea with the addition of nickel chloride to provide nickel ions and ethylendiammine (ED) to complex. The deposition from the solution described having 1:2 as a Ni/ED molar ratio gave interesting results in terms of adhesion to aluminium and uniformity of the deposition. The electrochemical study of the solution is provided. Application of electrodeposited Watt’s nickel and electroless NiP was also attempted on the layers from ionic liquid. The morphological characterisation proved the quality of the layers, while a corrosion study demonstrated the protective properties of the coatings obtained.

A widely used method to protect steel surfaces from corrosion is the application of a sacrificial layer of a less noble metal, which undergoes preferential corrosion due to galvanic coupling. The most used material is zinc, a metal readily available and easy to apply on components presenting large areas. However, zinc is far more reactive than iron, and the thickness of material needed to effectively prevent corrosion represents an issue for some applications, such as coatings for the automotive sector or the aerospace field. A possible solution can be the alloying of zinc with a metal of the iron group, thus increasing the nobility of the layer. By doing this the corrosion potential is shifted to values closer to iron, inducing a slower consumption of the sacrificial layer. Nickel, having a suitable equilibrium potential, is the most used metal, providing an excellent corrosion protection with respect to pure zinc. The coatings obtained are times more resistant to corrosion than pure zinc and are currently studied as alternatives to cadmium. Zn–Ni alloys are reasonably easy to electrodeposit, and the plating of corrosion efficient coatings was performed in the past from acidic and alkaline electrolytes. It is well-known that the best protective properties are achieved when the alloy presents a single γ phase, a condition that can be attained by controlling properly the plating parameters and electrolyte formulation. It is interesting to point out that the plated γ phase can be a metastable structure, as the Zn–Ni phase diagram predicts lattice distributions of the Ni atoms in contrast with the experimental results. The reasons for the observed metastability and the thermodynamic properties of Zn–Ni have been elucidated previously starting from the analysis of the equilibrium conditions of the different phases. It was demonstrated that Zn–Ni electroplated alloys from an alkaline bath follow the theoretical simulations, thus validating the interpretation provided. Zn–Ni can be plated also by means of pulsed electrodeposition, a method suitable to achieve more refined microstructures and compact layers. This change in microstructure also improves the corrosion behavior and the distribution of the residual stresses. Zn–Ni alloys having compositions in the range 14–18 wt-% are electrodeposited using direct current DC and pulse current PC in a cyanide-free alkaline electrolyte. Homogeneous and compact layers, suitable for corrosion protection, are obtained. Contrary to the common acceptance, X-ray diffraction spectra and differential scanning calorimetry thermal analysis show that the electrodeposited γ alloy by DC plating in electrolytes with complexant-additive agents has to be regarded as a metastable phase, whose atomic arrangement is different from that of the equilibrium γ intermetallic compound. A model for atomic distribution and the Gibbs free-energy function for the DC electrodeposited phase are discussed. It is found that PC deposited alloys from additive-free electrolytes present the same metastable behavior attributed to the DC plated homologues in electrolytes with complexant-additive agents. The corrosion behavior is found to be dependent on the duty cycle applied during PC deposition, as evidence of the different microstructures obtained in varying the parameters.

Synthesis and characterisation of nanocomposite coatings consisting of Ag doped TiO2 nanocrystals at different concentrations have been carried out. Composites were obtained by electrochemical deposition using a slightly alkaline cyanide free electrolyte containing AgNO3 as Ag precursors. Morphology and crystalline structure of the Ag/TiO2 hybrid materials with up to 8·5 vol.‐%TiO2 were compared with those of pure Ag coatings. The presence of TiO2 nanoparticles in the bath led to an increase in the degree of orientation of crystallites on [111] and [311] crystallographic directions. During the electrodeposition, the presence of TiO2 particles at the electrode/electrolyte interface retards the crystal growth, and hence, the composites possess smaller grain sizes. The surface morphology observations show that TiO2 nanocrystals were attached within the metallic matrix surface, and the appearance of the surface indicates a porous structure with different geometrically shaped grains; this is also confirmed by ...

Pulse plating of manganese–copper alloys from a sulphate solution with the addition of ammonium sulphate at pH 6·7 has been studied. The Mn–Cu electrodeposition system is characterised by steady st...