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The process of oxygen evolution reaction (OER) for water splitting is intricate and demands a substantial amount of energy. It necessitates the utilization of catalysts that are both highly efficient and durable in order to overcome the slow reaction kinetics. Amorphous, high-entropy oxide nanoparticles were prepared using simple one-step coprecipitation in this work. Due to highly disordered atomic arrangement in the amorphous structure of these catalysts and their high specific surface area, they compete to form active sites in the OER. Among them, IrRuCrFeCoNiO x demonstrated the optimal OER catalytic activity, requiring just a low overpotential (190 mV) with minimal Tafel slope (51.1 mV dec−1) to achieve the current density of 10 mA cm−2 in 1 M KOH. Through surface self-reconstruction in the OER, a crystalline active layer with a thickness of several nanometers formed on the catalyst's surface. The stable core-shell nanoarchitectures composed of crystalline and amorphous regions substantially improved the stability of the catalyst. This work verified the effectiveness of high-entropy design and the significant improvement of noble metal doping on OER performance. It develops a new OER catalyst for water splitting with great activity and stability. [Display omitted] • Amorphous high-entropy oxide nanoparticles were prepared with a simple one-step coprecipitation method. • By introducing a large amount of anions "CO 3 2−", the charge transfer ability of catalyst was greatly improved. • The valence state oscillation and multi-metallic synergistic effect were beneficial to the enhanced OER activity. • The stable core-shell structure composed of crystalline and amorphous regions substantially improved the OER stability. [ABSTRACT FROM AUTHOR]

A green separation routes for Fe and Ti from ilmenite via molten salt electrolysis is proposed in CaCl 2 -NaCl-CaO molten salt. FeTiO 3 powder can be dissolved into the molten salt, directly. In the process, CaTiO 3 is formed by the reaction of TiO 3 2- and Ca2+ in molten salt components. Pure iron is obtained under the controllable regulation of electrolysis parameters such as cell voltage or electrolysis temperature. Fe is deposited on the cathode by the selective electroreduction of Fe2+ with 2 electrons transfer process. Ti through the consecutive two-steps with 4 electrons transfer electroreduction process of TiO 3 2- is obtained: TiO 3 2- → TiO →Ti. FeTi and Fe 2 Ti alloy is also obtained through reaction of Fe and Ti. The electroreduction of Fe2+ and TiO 3 2- is limited by its diffusion. This approach provides a one-step green and sustainable separation of Fe and Ti from ilmenite (FeTiO 3). The main product of Fe and CaTiO 3 can be used for the field of catalyst, architecture, aerospace and energy storage materials. • A green strategy for extraction of iron and titanium from FeTiO 3 is proposed. • The solubility of FeTiO 3 in CaCl 2 -NaCl-CaO mixed molten salt is evaluated. • High purity iron is obtained from FeTiO 3 through electrolysis parameter controlment in molten salt. • Molten salt electrolysis mechanism and electrochemical dynamic has been studied. [ABSTRACT FROM AUTHOR]

Abstract: Pb(Mg1/3Ta2/3)O3–Pb(Mn1/3Sb2/3)O3–Pb(Zr x Ti1−x )O3 quaternary piezoelectric ceramics with different compositions near the morphotropic phase boundary were synthesized using a conventional solid state reaction method. The phases, microstructures, ferroelectric, piezoelectric and dielectric properties of the system were investigated. A transition from rhombohedral to tetragonal phase was observed as the Zr/Ti ratio decreased. The P–E loops presented pinched shapes at low electric fields and the distortions disappeared at high electric fields. The dielectric study revealed a diffuse phase transition behavior in the ceramics. The optimal dielectric and piezoelectric properties ɛ r =817, d 33 =285pC/N, k p =0.55, T C =302°C, tan δ =0.4% and Q m =1600 of the ceramics were obtained at the composition of Zr/Ti=50/50. Vibration velocity at ΔT =20°C was found as high as 0.74m/s for this composition, which was almost 2.5 times as that of the commercial hard PZT ceramics. [ABSTRACT FROM AUTHOR]