A versatile route to synthesizing bulk and supported nickel phosphides by thermal treatment of a mechanical mixing of nickel chloride and sodium hypophosphite

Designing transition metal-based porous architectures for supercapacitor electrodes: a review

Over the past decade, transition metal (TM)-based electrodes have shown intriguing physicochemical properties and widespread applications, especially in the field of supercapacitor energy storage owing to their diverse configurations, composition, porosity, and redox reactions. As one of the most intriguing research interests, the design of porous architectures in TM-based electrode materials has been demonstrated to facilitate ion/electron transport, modulate their electronic structure, diminish strain relaxation, and realize synergistic effects of multi-metals. Herein, the recent advances in porous TM-based electrodes are summarized, focusing on their typical synthesis strategies, including template-mediated assembly, thermal decomposition strategy, chemical deposition strategy, and host-guest hybridization strategy. Simultaneously, the corresponding conversion mechanism of each synthesis strategy are reviewed, and the merits and demerits of each strategy in building porous architectures are also discussed. Subsequently, TM-based electrode materials are categorized into TM oxides, TM hydroxides, TM sulfides, TM phosphides, TM carbides, and other TM species with a detailed review of their crystalline phase, electronic structure, and microstructure evolution to tune their electrochemical energy storage capacity. Finally, the challenges and prospects of porous TM-based electrode materials are presented to guide the future development in this field.

Principles of Design and Synthesis of Metal Derivatives from MOFs

Materials derived from metal-organic frameworks (MOFs) have demonstrated exceptional structural variety and complexity and can be synthesized using low-cost scalable methods. Although the inherent instability and low electrical conductivity of MOFs are largely responsible for their low uptake for catalysis and energy storage, a superior alternative is MOF-derived metal-based derivatives (MDs) as these can retain the complex nanostructures of MOFs while exhibiting stability and electrical conductivities of several orders of magnitude higher. The present work comprehensively reviews MDs in terms of synthesis and their nanostructural design, including oxides, sulfides, phosphides, nitrides, carbides, transition metals, and other minor species. The focal point of the approach is the identification and rationalization of the design parameters that lead to the generation of optimal compositions, structures, nanostructures, and resultant performance parameters. The aim of this approach is to provide an inclusive platform for the strategies to design and process these materials for specific applications. This work is complemented by detailed figures that both summarize the design and processing approaches that have been reported and indicate potential trajectories for development. The work is also supported by comprehensive and up-to-date tabular coverage of the reported studies.

Bimetallic phosphide hollow nanocubes derived from a prussian-blue-analog used as high-performance catalysts for the oxygen evolution reaction

Bimetallic phosphide (Ni_xFe_1−x)₂P hollow nanocubes were prepared from PBAs as highly active and stable OER electrocatalysts.

Highly Efficient and Robust Nickel Phosphides as Bifunctional Electrocatalysts for Overall Water-Splitting

To search for the efficient non-noble metal based and/or earth-abundant electrocatalysts for overall water-splitting is critical to promote the clean-energy technologies for hydrogen economy. Herein, we report nickel phosphide (NixPy) catalysts with the controllable phases as the efficient bifunctional catalysts for water electrolysis. The phases of NixPy were determined by the temperatures of the solid-phase reaction between the ultrathin Ni(OH)2 plates and NaH2PO2·H2O. The NixPy with the richest Ni5P4 phase synthesized at 325 °C (NixPy-325) delivered efficient and robust catalytic performance for hydrogen evolution reaction (HER) in the electrolytes with a wide pH range. The NixPy-325 catalysts also exhibited a remarkable performance for oxygen evolution reaction (OER) in a strong alkaline electrolyte (1.0 M KOH) due to the formation of surface NiOOH species. Furthermore, the bifunctional NixPy-325 catalysts enabled a highly performed overall water-splitting with ∼100% Faradaic efficiency in 1.0 M KOH electrolyte, in which a low applied external potential of 1.57 V led to a stabilized catalytic current density of 10 mA/cm(2) over 60 h.

Influence of rare earth metals on structure and performance of Ni2P/MCM-41 hydrodesulfurisation catalysts

A series of rare-earth-modified M-Ni2P/MCM-41 (M=Pr, Nd, Ce, La, Y) catalysts has been prepared by means of a temperature-programmed reduction method. The prepared catalysts were characterised by X-ray diffraction, N2-adsorption specific surface area measurements, X-ray photoelectron spectroscopy and CO uptake. The effects of rare earth metals on catalyst activity for hydrodesulfurisation (HDS) of dibenzothiophene (DBT) were studied. The results showed that the addition of rare earth metals increases the surface area and pore volume of the catalysts. Rare earth metals can promote formation of the Ni2P phase and induce a better Ni2P dispersion but they do not change the mechanism of HDS of DBT. Pr-Ni2P/MCM-41 exhibited the highest HDS activity. At reaction temperature of 300 °C, pressure of 3.0 MPa, hydrogen/oil volume ratio of 500, and weight hourly space velocity(WHSV) of 6.0 h−1, the addition of Pr increased the conversion of HDS of DBT by 16.7%.

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.