Synthesis of uniform-sized bimetallic iron–nickel phosphide nanorods

A theoretical investigation on the structural stability, superconductivity, and optical and thermodynamic properties of Ir2P under pressure

The potential applications of Ir2P are promising due to its desirable hardness, but its fundamental properties are still not fully understood. In this study, we present a systematic investigation of Ir2P's structural, electronic, superconducting, optical, and thermodynamic properties of Ir2P under pressure. Our calculations show that Ir2P has a Fm3̄m structure at ambient pressure, which matches well with experimental data obtained from high-pressure synchrotron X-ray diffraction. As pressure increases, a transition from the Fm3̄m to the I4/mmm phase occurs at 103.4 GPa. The electronic structure and electron-phonon coupling reveal that the Fm3̄m and I4/mmm phases of Ir2P are superconducting materials with superconducting transition temperatures of 2.51 and 0.89 K at 0 and 200 GPa, respectively. The optical properties of Ir2P indicate that it has optical conductivity in the infrared, visible, and ultraviolet regions. Additionally, we observed that the reflectivity R(ω) of Ir2P is higher than 76% in the 25-35 eV energy range at different pressures, which suggests that it could be used as a reflective coating. We also explored the finite-temperature thermodynamic properties of Ir2P, including the Debye temperature, the first and second pressure derivatives of the isothermal bulk modulus, and the thermal expansion coefficient up to 2000 K using the quasi-harmonic Debye model. Our findings offer valuable insights for engineers to design better devices.

Nitrogen-Doped Mixed-Phase Cobalt Nanocatalyst Derived from a Trinuclear Mixed-Valence Cobalt(III)/Cobalt(II) Complex for High-Performance Oxygen Evolution Reaction

Because of a continuous increase in energy demands and environmental concerns, a focus has been on the design and construction of a highly efficient, low-cost, environmentally friendly, and noble-metal free electrocatalyst for energy technology. Herein we report facile synthesis of the mixed-valence trinuclear cobalt complex 1 by the reaction of 2-amino-1-phenylethanol and CoCl₂·6H₂O in methanol as the solvent at room temperature. Further, 1 was reduced by using aqueous N₂H₄ as a simple reducing agent, followed by calcination at 300 °C for 3 h, yielding a nitrogen-doped mixed phase cobalt [β-Co(OH)₂ and CoO] nanocatalyst (N@MPCoNC). Both 1 and N@MPCoNC were characterized by various physicochemical techniques. Moreover, 1 was authenticated by single-crystal X-ray diffraction studies. The hybrid N@MPCoNC reveals a unique electronic and morphological structure, offering a low overpotential of 390 mV for a stable current density of 10 mA cm^-2 with high durability. This N@MPCoNC showed excellent electrocatalytic as well as photocatalytic activity for oxygen evolution reaction compared to 1.

Novel synthesis of a NiMoP phosphide catalyst in a CH4-CO2 gas mixture

NiMo bimetallic phosphide was synthesized from its corresponding oxidic precursor in a 1 : 1 CH₄ : CO₂ gas mixture for the first time. The in situ synthesized NiMoP phase in the feed for CH₄-CO₂ reforming can exhibit a higher activity compared to the one prepared in H₂.

In pursuit of advanced materials from single-source precursors based on metal carbonyls

In this perspective, the development of single-source precursors and their relative advantages over multiple source approaches for the synthesis of metal pnictide solid state materials is explored. Particular efforts in the selective production of iron phosphide materials for catalytic applications are discussed, especially directed towards the hydrogen evolution and oxygen evolution reactions of water splitting.

Phase-segregated NiP x @FeP y O z core@shell nanoparticles: ready-to-use nanocatalysts for electro- and photo-catalytic water oxidation through in situ activation by structural transformation and spontaneous ligand removal

The phase-segregated NiP_x@FeP_yO_z core@shell NPs act as a colloidally stable, ready-to-use, and excellent OER active transition metal phosphide-based catalyst.

The high overpotential of the oxygen evolution reaction is a critical issue to be overcome to realize efficient overall water splitting and enable hydrogen generation powered by sunlight. Homogeneous and stable nanoparticles (NPs) dispersed in solvents are useful as both electrocatalysts and cocatalysts of photocatalysts for the electro- and photo-catalytic oxygen evolution reaction, respectively, through their adsorption on various electrode substrates. Here, phase-segregated NiP_x@FeP_yO_z core@shell NPs are selectively synthesized by the reaction of Fe(CO)₅ with amorphous NiP_x seed-NPs. The NiP_x@FeP_yO_z NPs on conductive substrates exhibit higher electrocatalytic activity in the oxygen evolution reaction than those of other metal phosphide-based catalysts. The NiP_x@FeP_yO_z NPs can also be used as a cocatalyst of an anodic BiVO₄ photocatalyst to boost the photocatalytic water oxidation reaction. The excellent catalytic activity and high stability of the NiP_x@FeP_yO_z NPs without any post-treatments are derived from in situ activation through both the structural transformation of NiP_x@FeP_yO_z into mixed hydroxide species, (Ni, Fe)O_xH_y, and the spontaneous removal of the insulating organic ligands from NPs to form a smooth and robust (Ni, Fe)O_xH_y/substrate heterointerface during the oxygen evolution reaction.

A facile solution-phase synthesis of cobalt phosphide nanorods/hollow nanoparticles

A simple one-step solution-phase synthesis of cobalt phosphide nanorods (NRs) and hollow nanoparticles (NPs) has been reported in this paper. The phase and morphology evolutions of cobalt phosphide were researched by varying the reaction conditions. The detailed research confirms that oleylamine (OAm) in the reaction firstly reduces Co(acac)2 to the Co phase and the reaction between P atoms from TOP and Co atoms results in the Co2P phase. The as-synthesized NRs and NPs show superparamagnetic behavior at room temperature and ferromagnetic properties at 2 K. The current route provides a new and general chemical method for tunable preparation of cobalt phosphide nanostructures, which are important for further magnetic and catalytic studies.

Mechanical mixtures of metal oxides and phosphorus pentoxide as novel precursors for the synthesis of transition-metal phosphides

This study presents a new type of precursor, mechanical mixtures of metal oxides (MOs) and phosphorus pentoxide (P2O5) are used to synthesize Ni2P, Co2P and MoP phosphides by the H2 reduction method. In addition, this is first report of common solid-state P2O5 being used as a P source for the synthesis of metal phosphides. The traditional precursors are usually prepared via a complicated preparation procedure involving dissolution, drying and calcination steps. However, these novel MOs/P2O5 precursors can be obtained only by simple mechanical mixing of the starting materials. Furthermore, unlike the direct transformation from amorphous phases to phosphides, various specific intermediates were involved in the transformation from MOs/P2O5 to phosphides. It is worthy to note that the dispersions of Ni2P, Co2P and MoP obtained from MOs/P2O5 precursors were superior to those of the corresponding phosphides prepared from the abovementioned traditional precursors. It is suggested that the morphology of the as-prepared metal phosphides might be inherited from the corresponding MOs. Based on the results of XRD, XPS, SEM and TEM, the formation pathway of phosphides can be defined as MOs/P2O5 precursors → complex intermediates (metals, metal phosphates and metal oxide-phosphates) → metal phosphides.

An efficient method for the synthesis of nickel phosphide nanocrystals via thermal decomposition of single-source precursors

We report an efficient method for the synthesis of nickel phosphide NCs for the first time. The size of Ni₂P NCs can be controlled by changing reaction temperature and OAm quantity. The phase of nickel phosphide NCs can be controlled by increasing reaction time.

A novel synthetic route to transition metal phosphide nanoparticles

A novel synthetic route was developed to prepare nano-sized and well-dispersed phosphides of transition metals (Mo, Ni, and Co) from their corresponding oxide precursors.

One-step synthesis of nickel and cobalt phosphide nanomaterials via decomposition of hexamethylenetetramine-containing precursors

New hexamethylenetetramine (HMT)-containing precursors were used to prepare well dispersed Ni₂P and Co₂P nanoparticles.