Design of cost-effective, highly efficient and stable bifunctional electrocatalysts for overall water splitting is necessary for renewable energy systems. In this study, NiCoP nanowire arrays grown on 3D Ni foam (NiCoP NWAs/NF) were successfully synthesized by a two-step method, which were developed as novel bifunctional electrocatalysts for evaluating in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Their special cone nanostructure and bifunctional crystal structure enable the electrocatalysts to display remarkable electrocatalytic performance and stability for OER and HER (maintained for 28 h in the long-term HER and OER stability test with slight attenuation). The electrodes have very low overpotentials of 197 mV and 370 mV for HER and OER in 1.0 M KOH at a high current density of 100 mA cm⁻², respectively. All the merits can be attributed to several parameters: the inherent nature of transition metal phosphides, the presence of a bimetal synergetic effect, special morphology design, and the formation of “secondary” electrocatalysts on the surface of NiCoP. Meanwhile, the excellent bifunctional electrocatalysts can be developed as both anode and cathode of an alkaline electrolyzer (1.0 M KOH) which needs a cell voltage of 1.64 V to achieve 20 mA cm⁻² current density.

Single crystals of the title compound, tris-odium divanadium(III) tris-(orthophosphate), were grown from a self-flux in the system Na(4)P(2)O(7)-NaVP(2)O(7). Na(3)V(2)(PO(4))(3) belongs to the family of NASICON-related structures and is built up from isolated [VO(6)] octa-hedra (3. symmetry) and [PO(4)] tetra-hedra (.2 symmetry) inter-linked via corners to establish the framework anion [V(2)(PO(4))(3)](3-). The two independent Na(+) cations are partially occupied [site-occupancy factors = 0.805 (18) and 0.731 (7)] and are located in channels with two different oxygen environments, viz sixfold coordination for the first (. symmetry) and eightfold for the second (.2 symmetry) Na(+) cation.

Doping with metal ions can improve the electrochemical performance of Na₃V₂(PO₄)₃ (NVP) as a cathode material for SIBs. Herein, Na_3+xV_2−xM^II _x(PO₄)₃/C composites with low Co- and Cu-doping contents (x – 0, 0.01, 0.03, 0.05) have been fabricated by a facile sol–gel method. XRD, ICP-AES and XPS studies show that doping with Co²⁺ and Cu²⁺ does not alter the NVP structure of the material, and cobalt or copper successfully substitute the vanadium in its site. Raman and HRTEM data show the presence of an amorphous carbon coating on the phosphate surface, which increases the electronic conductivity of composites. Impedance spectroscopy suggests that low-level doping has significantly increased the electrical conductivity of the NVP matrix. Among all the samples of the compound, Na_3.01V_1.99Co_0.01(PO₄)₃/C (capacity of 116 mA h g⁻¹ at 0.5C) and Na_3.03V_1.97Cu_0.03(PO₄)₃/C (capacity of 114 mA h g⁻¹ at 0.5C) demonstrate the highest electrochemical ability. Moreover, even cycling at a high rate of 10C, an excellent reversible capacity is maintained at about 80% of the initial values (in the range of 72–89 mA h g⁻¹) after 1000 cycles. The presented work analyzes the advantages of low doping and the nature of the doping metal in relation to the electrochemical properties of the NASICON-type structure, which will facilitate further commercialization of SIBs.

Manganites are multifunctional materials which are widely used in both technology and devices. In this article, new prospects of their use as nanoparticles for various types of applications are demonstrated. For that, the ferromagnetic nanopowder of La_0.6Sr_0.4MnO₃ has been synthesized by the sol–gel method with a subsequent annealing at 700–900 °C. The crystal structure, phase composition and morphology of nanoparticles as well as magnetic, magnetothermal and electrocatalytic properties have been studied comprehensively. The critical sizes of superparamagnetic, single-domain, and multi-domain states have been determined. It has been established that an anomalously wide temperature range of magnetocaloric properties is associated with an additional contribution to the magnetocaloric effect from superparamagnetic nanoparticles. The maximum values of the specific loss power are observed in the relaxation hysteresis region near the magnetic phase transition temperature. The electrochemical stability and features of the decomposition of nanoparticles in 1 M KOH and Na₂SO₄ electrolytes have been determined. A decrease in the particle size contributes to an increase in electrocatalytic activity for overall water splitting. Magnetocaloric and electrocatalytic results of the work indicate the prospects for obtaining the possibility of changing the temperature regime of electrocatalysis using contactless heating or cooling.