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Electrolytic water splitting with evolution of both hydrogen (HER) and oxygen (OER) is an attractive way to produce clean energy hydrogen. It is critical to explore effective, but low-cost electrocatalysts for the evolution of oxygen (OER) owing to its sluggish kinetics for practical applications. Fe-based catalysts have advantages over Ni- and Co-based materials because of low costs, abundance of raw materials, and environmental issues. However, their inefficiency as OER catalysts has caused them to receive little attention. Herein, the FeS2/C catalyst with porous nanostructure was synthesized with rational design via the in situ electrochemical activation method, which serves as a good catalytic reaction in the OER process. The FeS2/C catalyst delivers overpotential values of only 291 mV and 338 mV current densities of 10 mA/cm2 and 50 mA/cm2, respectively, after electrochemical activation, and exhibits staying power for 15 h.

A novel, economic and environmentally friendly anticorrosion coating material for metals is introduced and investigated in this paper. For this purpose, camphor-sulfonic-acid/graphene-doped poly(o-toluidine) composites (MG/CSA@POT) were fabricated using in-situ polymerization with (NH4)2S2O8 as an oxidant. The structure and the morphology of MG/CSA@POT were analyzed using FTIR (Fourier-transform infrared spectroscopy), XRD (X-ray diffraction), and SEM (Scanning Electron Microscope). Multilayer graphene (MG)/CSA@POT-polyurethane composite coatings (MG/CSA@POT-WPU) were prepared on the surface of a carbon steel substrate by mixing MG/CSA@POT with waterborne polyurethane via blending. The corrosion performance of the MG/CSA@POT-WPU composite coatings in a 3.5% NaCl solution was studied with a corrosion electrochemical method. The results showed that 5-MG/CSA@POT-WPU had the best shielding effect on corrosive media and the lowest corrosion rate (1.02 × 10−6 mm/year) compared to other coatings while its inhibition efficiency reached 99.96%.

Inexpensive electrolyte systems and readily available rare-earth (RE) precursors are necessary for the facile recovery of RE metals at the lowest temperature, which will allow the sustainable development of RE metal-based industries. Inspired by previous reports on Nd electrodeposition in various expensive and specialized ionic liquids (ILs), herein, we developed a practical, green, and cost-effective Nd-containing solvate IL composed of an organic solvent [(1,3-dimethyl-2-imidazolidinone)] and Nd (CF3SO3)3; the IL is well suited for Nd electrodeposition using LiNO3. The electrolyte structure and electrochemical mechanism of the IL were elucidated through physicochemical analyses and cyclic voltammetry. The role of nitrate was investigated in detail. Nd was successfully electrodeposited using the proposed method, as confirmed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analyses. Thus, this work provides a firm theoretical basis and a practical strategy for the cost-effective bulk electrochemical extraction of RE metals at relatively low temperatures.

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