The ability to control chemical and physical structuring at the nanometre scale is important for developing high-performance thermoelectric materials. Progress in this area has been achieved mainly by enhancing phonon scattering and consequently decreasing the thermal conductivity of the lattice through the design of either interface structures at nanometre or mesoscopic length scales or multiscale hierarchical architectures. A nanostructuring approach that enables electron transport as well as phonon transport to be manipulated could potentially lead to further enhancements in thermoelectric performance. Here we show that by embedding nanoparticles of a soft magnetic material in a thermoelectric matrix we achieve dual control of phonon- and electron-transport properties. The properties of the nanoparticles-in particular, their superparamagnetic behaviour (in which the nanoparticles can be magnetized similarly to a paramagnet under an external magnetic field)-lead to three kinds of thermoelectromagnetic effect: charge transfer from the magnetic inclusions to the matrix; multiple scattering of electrons by superparamagnetic fluctuations; and enhanced phonon scattering as a result of both the magnetic fluctuations and the nanostructures themselves. We show that together these effects can effectively manipulate electron and phonon transport at nanometre and mesoscopic length scales and thereby improve the thermoelectric performance of the resulting nanocomposites.

Developing highly efficient and stable electrocatalysts plays an important role in energy-related electrocatalysis fields. Transition-metal phosphides (TMPs) possess a series of advantages, such as high conductivity, earthabundance reserves, and good physicochemical properties, therefore arousing wide attention. In this review, the electrochemical activity origin of TMPs, allowing the rational design and construction of phosphides toward various energy-relevant reactions is first discussed. Subsequently, their unique energy-related electrocatalysis nature toward hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR), carbon dioxide reduction reaction (CO 2 RR), nitrogen reduction reaction (NRR), urea oxidation reaction (UOR), methanol oxidation reaction (MOR), and others is highlighted. Then, the TMPs' synthetic strategies are analyzed and summarized systematically. Finally, the existing key issues, countermeasures, and the future challenges of TMPs toward efficient energy-related electrocatalysis are briefly discussed.

crisis and environmental issue. [1] Electrochemical water electrolysis offers a promising and effective strategy to produce high-quality H 2 without carbon emission. [2] However, the sluggish kinetics of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been a huge challenge for water splitting, which has spurred researchers for exploiting high-efficiency electrocatalysts with reduced dynamic overpotentials. [3] AlthoughPt-based materials and Ru/Ir-based oxides are still known as the most efficient catalysts for HER and OER, they suffer from low abundance and high prices, leading to difficulties in the largescale commercial application. [4] In addition, the most obtained electrocatalysts are not capable of possessing both excellent HER and OER performance in a same electrolyte due to incompatibility of activity over different pH ranges. [5] Therefore, constructing non-noble metal bifunctional electrocatalysts with high performance and cost-effectiveness has become a hot spot for efficient overall water splitting.Recently, low-cost nickel chalcogenides, such as NiS, NiS 2 , and Ni 3 S 2 , have attracted enormous attention for electrolytic water splitting. [6] In particular, the Ni 3 S 2 electrocatalyst has been widely researched due to high conductivity and unique structure configuration, while the imprisoned HER/OER activity Rational design and construction of bifunctional electrocatalysts with excellent activity and durability is imperative for water splitting. Herein, a novel topdown strategy to realize a hierarchical branched Mo-doped sulfide/phosphide heterostructure (Mo-Ni 3 S 2 /Ni x P y hollow nanorods), by partially phosphating Mo-Ni 3 S 2 /NF flower clusters, is proposed. Benefitting from the optimized electronic structure configuration, hierarchical branched hollow nanorod structure, and abundant heterogeneous interfaces, the as-obtained multisite Mo-Ni 3 S 2 /Ni x P y /NF electrode has remarkable stability and bifunctional electrocatalytic activity in the hydrogen evolution reaction (HER)/oxygen evolution reaction (OER) in 1 m KOH solutions. It possesses an extremely low overpotential of 238 mV at the current density of 50 mA cm −2 for OER. Importantly, when assembled as anode and cathode simultaneously, it merely requires an ultralow cell voltage of 1.46 V to achieve the current density of 10 mA cm −2 , with excellent durability for over 72 h, outperforming most of the reported Ni-based bifunctional materials. Density functional theory results further confirm that the doped heterostructure can synergistically optimize Gibbs free energies of H and O-containing intermediates (OH*, O*, and OOH*) during HER and OER processes, thus accelerating the catalytic kinetics of electrochemical water splitting. This work demonstrates the importance of the rational combination of metal doping and interface engineering for advanced catalytic materials.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.

Developing high-efficiency and stable oxygen evolution reaction (OER) materials remains a great challenge, especially in an acidic medium. In this study, we report the first synthesis of phase-pure RuB2 by using a salt melt of potassium chloride and lithium chloride as the solvent. When used as an electrocatalyst in 0.5 M sulfuric acid, the as-prepared RuB2 needs an overpotential of only 223 mV for the OER to produce an operationally relevant current density of 10 mA cm–2. This is almost the smallest overpotential value for Ir/Ru-based acidic OER catalysts reported to date. More importantly, in the acidic full water splitting, RuB2 exhibits outstanding activity and stability, which merely needs a cell voltage of 1.525 V to reach a current density of 10 mA cm–2, lower than those of the most bifunctional electrocatalysts reported in acid electrolytes. Theoretical calculation results further identify the formation of *OOH as the rate-determining step and the lower energy barrier for the RuB2 catalyst, improving the OER activity. This work represents a significant addition to exploring a new class of transition metal borides with outstanding activity in acidic water electrolysis and beyond.

Water splitting is a promising technology for sustainable conversion of hydrogen energy. The rational design of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) bifunctional electrocatalysts with superior activity and stability in the same electrolyte is the key to promoting their large‐scale applications. Herein, an ultralow Ru (1.08 wt%) transition metal phosphide on nickel foam (Ru–MnFeP/NF) derived from Prussian blue analogue, that effectively drivies both the OER and the HER in 1 m KOH, is reported. To reach 20 mA cm−2 for OER and 10 mA cm−2 for HER, the Ru–MnFeP/NF electrode only requires overpotentials of 191 and 35 mV, respectively. Such high electrocatalytic activity exceeds most transition metal phosphides for the OER and the HER, and even reaches Pt‐like HER electrocatalytic levels. Accordingly, it significantly accelerates full water splitting at 10 mA cm−2 with 1.470 V, which outperforms that of the integrated RuO2 and Pt/C couple electrode (1.560 V). In addition, the extremely long operational stability (50 h) and the successful demonstration of a solar‐to‐hydrogen generation system through full water splitting provide more flexibility for large‐scale applications of Ru–MnFeP/NF catalysts.