Development of efficient non-precious catalysts for seawater electrolysis is of great significance but challenging due to the sluggish kinetics of oxygen evolution reaction (OER) and the impairment of chlorine electrochemistry at anode. Herein, we report a heterostructure of Ni₃S₂ nanoarray with secondary Fe-Ni(OH)₂ lamellar edges that exposes abundant active sites towards seawater oxidation. The resultant Fe-Ni(OH)₂/Ni₃S₂ nanoarray works directly as a free-standing anodic electrode in alkaline artificial seawater. It only requires an overpotential of 269 mV to afford a current density of 10 mA·cm⁻² and the Tafel slope is as low as 46 mV·dec⁻¹. The 27-hour chronopotentiometry operated at high current density of 100 mA·cm⁻² shows negligible deterioration, suggesting good stability of the Fe·Ni(OH)₂/Ni₃S₂@NF electrode. Faraday efficiency for oxygen evolution is up to ∼ 95%, revealing decent selectivity of the catalyst in saline water. Such desirable catalytic performance could be benefitted from the introduction of Fe activator and the heterostructure that offers massive active and selective sites. The density functional theory (DFT) calculations indicate that the OER has lower theoretical overpotential than Cl₂ evolution reaction in Fe sites, which is contrary to that of Ni sites. The experimental and theoretical study provides a strong support for the rational design of high-performance Fe-based electrodes for industrial seawater electrolysis.

A reduced graphene oxide/copper (RGO/Cu) composite was fabricated by a surfactant free, electroless co-deposition technique. The graphene oxide (GO) sheets were reduced and RGO homogeneous distributed into the copper matrix. On the basis of nanoindentation, the presence of RGO and the increase of its content in matrix significantly raised the hardness of RGO/Cu composites. Here, the relevant strengthening effect and mechanisms involved in RGO-reinforced Cu composites were systematically evaluated. Especially, the addition of RGO in Cu matrix led to the compressive micro-strain, and the resulted distortion of the lattice parameter was calculated based on Cohen’s method. However, excessive addition of GO in the electrolyte could decrease the mechanical performance due to agglomeration of RGO. Apparently, the optimal concentration for GO dispersion in co-deposition solution was deserved to discuss. After a serious of relative experiments, we could get a conclusion that this method provided a new pathway for embedded graphene into the metal matrix to improve the mechanical properties of RGO-reinforced materials.

• Loading compressive stress deteriorated the cavitation erosion-corrosion resistance. • The synergetic mass loss (Ws) remarkably increased with loading compressive stress. • The applied of compressive stress has accelerated the corrosion of eutectoid “α + κ”. • W_CIE became the dominant factor of cavitation erosion-corrosion with loading stress.

The in-situ studies of the corrosion product film on nickel-aluminum bronze are significant for explaining the mechanism of its corrosion resistance. In this paper, the corrosion behavior of nickel-aluminum bronze and the formation process of the protective film in 3.5 wt % NaCl solution are systematically investigated. The results of scanning electron microscope analysis and electrochemical tests indicate that the corrosion resistance of nickel-aluminum bronze is improved due to the formation of the corrosion product film. The change of local electrochemical property on the corrosion product film during the immersion time is evaluated via in-situ scanning vibrating electrode technique, and it reveals the evolution rules of ionic flux in real time. The formation process of the protective film on different phases in nickel-aluminum bronze is observed directly by in-situ atomic force microscopy as height change measurements. The α phases at different locations present different corrosion behaviors, and the lamellar α phase within the α + κ_III eutectoid structure gets more serious corrosion attack. The κ phases establish a stable and dense protective film in short time, preventing the corrosion attack effectively. The β′ phase, however, suffers the most serious corrosion damage until a protective film is formed after 150 min of immersion.

Cu has recently received great interest as a potential candidate for glucose sensing to overcome the problems with noble metals. In this work, reduced graphene oxide-encapsulated Cu nanoparticles ([email protected]) have been prepared via an electrostatic self-assembly method. This core/shell composites were found to be more stable than conventional Cu-decorated graphene composites and bare copper nanoparticles in an air atmosphere because the graphene shell can effectively protect the Cu nanoparticles from oxidation. In addition, the obtained [email protected] composites also showed an outstanding electrocatalytic activity toward glucose oxidation with a wide linear detection range of 1 μM to 2 mM, low detection limit of 0.34 μM (S/N = 3), and a sensitivity of 150 μA mM^–1 cm^–2. Moreover, [email protected] composites exhibited a satisfactory reproducibility, selectivity, and long effective performance. These excellent properties indicated that [email protected] nanoparticles have great potential application in glucose detection.

Inhomogeneous structures with carbon nanotubes (CNTs), reinforced with Cu composite foams as the reinforcing skeletons (CNTs/Cu_f^®Cu), have been designed to overcome the paradox between strength and ductility or conductivity in copper matrix composites. The interface between CNTs and the copper matrix is usually weak, due to poor wettability and interaction. In this study, nickel nanoparticles are decorated onto CNTs to improve interfacial bonding. The broader interface transition area between CNTs and copper with Ni₃C interfacial products formed, and a combination of improved electrical conductivity (95.6% IACS), tensile strength (364.9 MPa), and elongation (40.6%) was achieved for the Ni-decorated CNTs/Cu_f^®Cu (Ni-CNTs/Cu_f^®Cu). In addition, the strengthening mechanisms are discussed in this study.