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The bimetallic nickel-cobalt phosphide (NiCoP) has been confirmed as an efficient electrocatalyst in water splitting. But little attention is paid to the selectivity and affinity of metal sites on hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a trace-Zn-doping (2.18 wt.%) NiCoP (Zn-NiCoP) whereby the nanoparticles self-aggregated to form elongated nanoneedles. We discover that both Co and Ni sites can be replaced by Zn. The Co substitution improves HER, while the Ni substitution dramatically reduces the energy barrier of the rate-determining step (*O → *OOH). The negative shift of d-band centers after Zn doping ameliorates the intermediate desorption. Therefore, Zn-NiCoP demonstrates superior electrocatalytic activity with overpotentials of 48 and 240 mV for HER and OER at 10 and 50 mA·cm−2, respectively. The cell voltage with Zn-NiCoP as both anode and cathode in water splitting was as low as 1.35 V at 10 mA·cm−2. [ABSTRACT FROM AUTHOR]

Rational design of electrocatalysts is the key to achieving sustainable oxygen evolution reaction (OER). The conjugation of metal organic frameworks (MOFs) with different multicomponent materials to precisely construct heterostructures is fascinating but remains a significant challenge due to different interface energies and nucleation kinetics. In this work, hollow multilayer heterogeneous catalyst (CoFeP/CoFeP/NP-C) was constructed using a rigid template sacrifice approach and an ion exchange strategy. By cleverly combining iron-based MOFs (MIL-88A, sacrifice template) nanorods, layered dihydroxides (LDH) nanosheets, and Prussian blue (PB) nancubes to form rich heterojunction and bimetallic phosphide catalysts, and by tuning the reaction kinetics and electron transfer capacities to enrich the active sites, ultimately promoting the intrinsic activity of the catalyst towards OER. Simultaneously, the co-doping of nitrogen and phosphorus in the heterostructure helped to adjust the electronic structure of the heterogeneous catalyst and the conductivity of the matrix, promoting the adsorption and desorption of OER intermediates on the catalyst surface. This work provides a new strategy for designing efficient and stable bimetallic phosphide electrocatalysts. A highly stable and OER electrocatalyst (CoFeP/CoFeP/NP-C) featuring porous and hollow configuration, numerous heterogeneous interfaces, co-doping defects, and abundant active species in a hierarchical heterostructure is reported, which is fabricated by a sacrifice template-assisted method and cation exchange strategy. [Display omitted] • Hollow multilayer heterostructure is designed via a sacrifice template approach. • Synergistic effect of heterointerface and co-doping enhance the catalytic active. • The CoFeP/CoFeP/NP-C delivers outstanding OER catalytic performance. [ABSTRACT FROM AUTHOR]

A simple hybrid system is constructed using CdS as photocatalyst and transition metal phosphides as cocatalysts for selectively photocatalytic formic acid decomposition under visible light irradiation at room temperature. By adjusting FA decomposition conditions, different products of H2, CO, or syngas can be obtained according to different demands. With the assistance of bimetallic phosphides as cocatalysts, the H2 and CO production efficiencies can reach up to 138.3 and 116.1 μmol mg−1 h−1 at pH = 1.5 and 9.2, respectively. At pH = 4.4, the syngas efficiency can reach up to 306.9 μmol mg−1 h−1, including 101.4 μmol mg−1 h−1 H2 and 205.5 μmol mg−1 h−1 CO. Moreover, the present heterogeneous system also exhibits excellent photocatalytic stability and still keeps high rates after the five‐cycle reaction, indicating its potential application value. [ABSTRACT FROM AUTHOR]

Developing high‐efficiency and stable bifunctional electrocatalysts for water splitting remains a great challenge. Herein, NiMoO4 nanowires as sacrificial templates to synthesize Mo‐doped NiFe Prussian blue analogs are employed, which can be easily phosphorized to Mo‐doped Fe2xNi2(1‐x)P nanotubes (Mo‐FeNiP NTs). This synthesis method enables the controlled etching of NiMoO4 nanowires that results in a unique hollow nanotube architecture. As a bifunctional catalyst, the Mo‐FeNiP NTs present lower overpotential and Tafel slope of 151.3 (232.6) mV at 100 mA cm−2 and 76.2 (64.7) mV dec−1 for HER (OER), respectively. Additionally, it only requires an ultralow cell voltage of 1.47 V to achieve 10 mA cm−2 for overall water splitting and can steadily operate for 200 h at 100 mA cm−2. First‐principles calculations demonstrate that Mo doping can effectively adjust the electron redistribution of the Ni hollow sites to optimize the hydrogen adsorption‐free energy for HER. Besides, in situ Raman characterization reveals the dissolving of doped Mo can promote a rapid surface reconstruction on Mo‐FeNiP NTs to dynamically stable (Fe)Ni‐oxyhydroxide layers, serving as the actual active species for OER. The work proposes a rational approach addressed by electron manipulation and surface reconstruction of bimetallic phosphides to regulate both the HER and OER activity. [ABSTRACT FROM AUTHOR]

The development of transition metal electrocatalysts with excellent HER, OER and HMFOR activity can accelerate the achievement of "carbon peaking and carbon neutrality". Herein, we report a simple structure modulation and morphological strategy for constructing Ni x Co y P-3 nanoneedles array with superhydrophilic/aerophobic surface. The small and well-dispersed nanoneedles can expose a larger electrochemical surface area. It has good mechanical stability, which can withstand the impact of violent bubbles at ampere-level current densities. Ni x Co y P-3 has a stronger H 2 O adsorption capacity than Ni 2 P, and can promote the adsorption and desorption of H* to facilitate the HER process. During the OER process, the formation of the Ni x Co y P-3/Ni x Co y OOH heterostructure is an important factor to stabilize oxygen evolution at ampere-level current densities. During the HMFOR process, Ni x Co y P-3 has a stronger HMF adsorption energy than Ni 2 P, and the generated FDCA can be desorbed from the Ni x Co y P-3 surface more easily. The overpotentials of the Ni x Co y P-3 are only 38.8 mV and 231.2 mV for HER and OER at 10 mA cm−2 in alkaline medium. When in the 1.0 M KOH + 50 mM HMF, only 1.37 V was required to reach a current density of 10 mA cm−2 of the Ni x Co y P-3 II Ni x Co y P-3 two-electrode system. Ni x Co y P-3 can drive 1000 mA cm−2 overall water splitting for 100 h of stable operation in 1 M KOH, validating its potential in industrial hydrogen production. • A trifunctional electrocatalyst by a simple structure modulation and morphological strategy is provided. • The nanoneedle array can withstand the impact of violent bubbles at large current densities. • Ni x Co y P-3 sample can drive 1000 mA cm−2 overall water splitting for 100 h of stable operation in 1 M KOH. • The formation of Ni x Co y P-3/Ni x Co y OOH is an important factor to stabilize oxygen evolution at large current densities. [ABSTRACT FROM AUTHOR]

Abstract Developing high‐efficiency and stable bifunctional electrocatalysts for water splitting remains a great challenge. Herein, NiMoO4 nanowires as sacrificial templates to synthesize Mo‐doped NiFe Prussian blue analogs are employed, which can be easily phosphorized to Mo‐doped Fe2xNi2(1‐x)P nanotubes (Mo‐FeNiP NTs). This synthesis method enables the controlled etching of NiMoO4 nanowires that results in a unique hollow nanotube architecture. As a bifunctional catalyst, the Mo‐FeNiP NTs present lower overpotential and Tafel slope of 151.3 (232.6) mV at 100 mA cm−2 and 76.2 (64.7) mV dec−1 for HER (OER), respectively. Additionally, it only requires an ultralow cell voltage of 1.47 V to achieve 10 mA cm−2 for overall water splitting and can steadily operate for 200 h at 100 mA cm−2. First‐principles calculations demonstrate that Mo doping can effectively adjust the electron redistribution of the Ni hollow sites to optimize the hydrogen adsorption‐free energy for HER. Besides, in situ Raman characterization reveals the dissolving of doped Mo can promote a rapid surface reconstruction on Mo‐FeNiP NTs to dynamically stable (Fe)Ni‐oxyhydroxide layers, serving as the actual active species for OER. The work proposes a rational approach addressed by electron manipulation and surface reconstruction of bimetallic phosphides to regulate both the HER and OER activity.

On the surface of nickel foam, carbon-doped bimetallic phosphide 0.5CDs-NiCoP/NF is effectively prepared using a facile hydrothermal and phosphorization technique. CDs doping produces a distinct urchin-like sample with more exposed active sites, larger surface area, and faster charge transfer. Furthermore, the CDs-doped heteroatoms caused further electron transfer, all of which resulted in These advantages provide the created 0.5CDs-NiCoP/NF with strong electrocatalytic capabilities and allow the 0.5CDs-NiCoP/NF to function well in hydrogen precipitation at a wide pH range. [Display omitted] The development of an efficient noble-metal-free and pH-universal electrocatalyst for the hydrogen evolution reaction (HER) would be highly significant for hydrogen (H 2) production via electrocatalytic water splitting. However, developing such a catalyst remains a formidable task. Herein, a strategy is proposed for the in situ fabrication of a novel urchin-like NiCoP microsphere catalyst (0.5CDs-NiCoP/NF) on nickel foam (NF) using carbon dots (CDs) as a directing agent. The strong bonding between the CDs and metals provides additional active sites, giving 0.5CDs-NiCoP/NF excellent electrocatalytic hydrogen evolution performance in environments ranging from acidic to basic. Moreover, the unique structure of 0.5CDs-NiCoP/NF endows this catalyst with low Tafel slopes of 73, 146 and 74 mV dec−1 for HER in acidic, neutral and alkaline conditions, respectively. This performance exceeds that of numerous other reported non-precious HER catalysts. In summary, this work offers a novel and efficient strategy for the design and synthesis of low-cost, efficient, and robust transition metal phosphides (TMPs) electrocatalysts. [ABSTRACT FROM AUTHOR]

Efficient and stable low‐cost catalysts are seriously lacking for industrial water electrolysis at large‐current‐density. To meet industrial‐scale hydrogen production, fully utilized active sites by a rational structure design is an attractive route. Herein, dynamic microstructure manipulation of bimetallic phosphide NiCoP is conducted. Among different microstructures for NiCoP, as‐obtained NiCoP‐120 at hydrothermal temperature of 120 °C, shows a special multiscale hierarchical structure from 3D‐nickel foam substrates, 2D‐nanosheets to 1D‐nanoneedles, which is conducive to efficient utilization of active sites and rapid gas release, thus manifesting outstanding electrocatalytic activities and stability as required by industry. To reach a current density of 10 and 1000 mA cm−2 for the hydrogen evolution reaction (HER), NiCoP‐120 requires ultra‐low overpotentials of 56 and 247 mV, respectively. Particularly, as a bifunctional catalyst, it only needs 1.981 V to drive the 1 A cm−2 overall water splitting and can maintain stable output for 600 h, which is superior to almost all reported non‐noble metal catalysts. Moreover, its application prospect in integrated green energy‐to‐hydrogen systems, including sunlight, wind, thermal, and lithium cells, is well demonstrated. This work provides a guiding strategy for the design of industrial water electrolysis catalysts and the establishment of an externally driven water‐splitting hydrogen production system. [ABSTRACT FROM AUTHOR]

Hydrogen generation from water splitting is of great prospect for the sustainable energy conversion. However, it is still challenging to explore stable and high-performance electrocatalysts toward hydrogen evolution reaction (HER) from saline water such as seawater due to the chloride corrosion. Herein, we developed a self-supported heterogeneous bimetallic phosphide (Ni2P-FeP) array electrode that possesses excellent HER performance in alkaline saline water with an overpotential of 89 mV at 10 mA·cm−2 and long-term stability over 90 h at 200 mA·cm−2. The analysis showed that the heterostructure between the interfaces of Ni2P-FeP plays a pivotal role in promoting the activity of catalyst. Moreover, the bimetallic phosphide nanoarrays can be employed as a shield for chlorine-corrosion resistance in the saline water, ensuring the long-term durability of hydrogen generation. When employed for alkaline saline water electrolysis, a current density of 100 mA·cm−2 is achieved at cell voltage of 1.68 V. This work presents an effective approach for the fabrication of high-performance electrode for HER in alkaline saline environments. [ABSTRACT FROM AUTHOR]

A practical dual-metal–organic-framework approach is proposed to fabricate heterogeneous bimetallic phosphide CoP/MoP hybrid, which shows boosted catalytic HER activity along with long-term stability in acidic and alkaline media. [Display omitted] Searching for efficient and cost-effective electrocatalysts for hydrogen evolution reaction (HER) is significantly desirable and challenging. Herein, N, P co-doped carbon-encapsulated CoP/MoP hybrid (CoP/MoP@NPC) is fabricated using dual-metal–organic-framework (dual-MOF) as precursor by a simple one-step phosphating process. When applied as an electrocatalyst toward the HER, the as-designed CoP/MoP@NPC hybrid shows efficiently catalytic performance with a lower overpotential of 183 mV to deliver a current density of 10 mA cm−2, smaller Tafel slope of 53.3 mV dec-1 as well as long-time stability for 10 h in 0.5 M H 2 SO 4 owing to the distinctive component and structural advantages. Furthermore, the electrode material also displays enhanced electrocatalytic HER activity in alkaline media. Importantly, this work provides an effective and feasible route for the construction of bimetallic phosphide electrocatalysts toward hydrogen production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalysts of Cu/Ni phosphides and Graphdiyne were obtained for the first time. • Integrated Graphdiyne can fairly improve the activity of OER in CuNiPx-GDY(1:1). • The introduced GDY can bring different active sites for OER and HER in the hybrid. • CuNiPx-GDY(1:1) shows extremely small η 10 of 178 mV and 110 mV for OER and HER. • Synergistic effect of GDY and TMPs availably accelerates water splitting process. Obtaining of non-noble metal catalyst with bifunctional effect for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting is highly desired to get high purity hydrogen. Here in, we design and fabricate Cu/Ni bimetallic phosphides with Graphdiyne (GDY) to form hybrid nanomaterial CuNiPx-GDY on Ni foam for the first time. The synergistical effect between GDY and transition metal phosphides, and the atomic scale heterojunctions between Cu 3 P and Ni 2 P, effectively accelerate the catalytical process both in HER and OER, resulting in extraordinarily small overpotentials of 178 mV and 110 mV at 10 mA cm−2 for OER and HER in CuNiPx-GDY(1:1) in 1 M KOH, respectively. Density functional theory results show that, compared with pure CuNiPx, the introduced GDY can considerably improve the activity of OER and generate different active sites for OER and HER in CuNiPx-GDY(1:1). Thus CuNiPx-GDY(1:1) exhibits good catalytical performance and stability as catalyst for overall water splitting. This study provides a new sight into the structure and catalytic properties of GDY and transition metal phosphides hybrid nanomaterial, and also offers a new way to obtain advanced materials with remarkable catalytic properties. [ABSTRACT FROM AUTHOR]

Achieving efficient electrocatalytic activity in two-dimensional (2D) MXene for advanced water splitting remains a significant challenge. In this work, 2D MXene was derived into sea urchin-like TiO 2 and used to load porous bimetallic phosphide (NiCoP x) nanorods to achieve three-dimensional (3D) TiO 2 -NiCoP x hierarchical heterostructures. The hierarchical heterostructures synthesized through hydrothermal and phosphating processes enable rich heterogeneous interfaces and fully exposed active sites, thereby facilitating efficient charge transfer and accelerating mass transfer rates. As a result, the TiO 2 -NiCoP x heterostructures inherit the low overpotential (311 mV at 10 mA cm−2) and long-term stability (current density retention of 94.1 % after 12 h) towards oxygen evolution reaction (OER). Importantly, the assembled TiO 2 -NiCoP x || Pt/C cell also exhibits remarkable water splitting performance. This contribution delivers a desirable opportunity for constructing efficient 2D MXene-based electrocatalysts with abundant active sites for water splitting. [Display omitted] • Hydrothermal strategy is proposed to construct 2D MXene derivatives. • Porous NiCoP x nanorods are tightly anchored on sea urchin-like TiO 2. • TiO 2 -NiCoP x hierarchical heterostructure exhibits excellent water splitting performance. [ABSTRACT FROM AUTHOR]

The exploration of bifunctional catalysts with high activity and durability is important for the electrolysis of urea–assisted hydrogen production. Therefore, we rationally designed a NiCoP catalyst with a bimetallic synergistic effect to realize the strategy of promoting the bifunctional activity of hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) at high current density. Corresponding X-ray diffractogram (XRD) and X-ray photoelectron spectroscopy (XPS) analyses prove the chemical composition and successful synthesis of the NiCoP. Electrochemical activity tests indicate that the NiCoP requires a potential of 1.27 V to achieve 10 mA cm−2, and shows good UOR activity. In the overall urea electrolysis (UOR || HER), NiCoP can maintain the high current density of 200 mA cm−2 for 142 h at 1.67 V. The NiCoP exhibits excellent bifunctional catalytic activity and durability. NiCoP as bifunctional catalyst for efficient electrolysis of urea-assisted hydrogen production at high current density. [Display omitted] • NiCoP bifunctional catalyst expose more catalytically active sites. • NiCoP accelerates catalytic activity through bimetallic synergistic effect. • NiCoP can maintain the high current density (200 mA cm−2) for 142 h at 1.67 V. [ABSTRACT FROM AUTHOR]

The exploitation of non noble metal oxygen evolution reaction (OER) electrocatalysts with tuneable electronic structures and chemical compositions is an effective way to improve water splitting, which is of great significance to the development of clean energy. Here, we report a zirconium-induced transition metal phosphide supported by nitrogen-doped carbon fiber (P–CoFeZr/NCBC) as an efficient electrocatalyst for the OER. The electrocatalyst is produced in situ on the surface of nitrogen-doped carbon fibers to form an open structure, achieving a high concentration of active sites. Additionally, the electronic structure is modified through the introduction of zirconium to increase the intrinsic activity of the electrocatalyst. These phenomena greatly enhance the oxygen evolution activity of the electrocatalyst. In alkaline media, P–CoFeZr/NCBC exhibits excellent catalytic activity and fast kinetics, with overpotentials and Tafel slopes of 300 mV and 51 mV/dec at 10 mA/cm2, and displays excellent long-term stability for more than 24 h at 50 mA/cm2. • N-doped carbon fibers loaded with Zr-induced bimetallic phosphides was synthesized. • The introduction of Zr improves the intrinsic activity of the electrocatalyst. • Abundant active sites in favor of OER are produced through N-doped carbon fibers. • P–CoFeZr/NCBC delivers OER performance of 300 mV and 51 mV/dec at 10 mA/cm2. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoPdP/KUSY nanoparticles synthesized by temperature programed reduction. • X-ray absorption fine-structure spectroscopy confirms Co-Pd alloy formation. • Fourier transform infrared spectroscopy of CO adsorption probes Co and Pd surface sites. • Co and Pd act synergistically in increasing the activity of hydrodeoxygenation of benzofuran. The synthesis of bimetallic CoPdP phosphides supported on potassium ion exchanged ultra-stable Y (KUSY) zeolites was studied and catalytic activity tests on the hydrodeoxygenation of a model pyrolysis oil compound, benzofuran, were conducted. Temperature programmed reduction (TPR) profiles revealed that Pd aided the reduction of the Co, lowering both the onset and peak temperatures for reduction. The catalyst structure was probed by X-ray diffraction (XRD) and extended X-ray adsorption fine structure (EXAFS), which showed the formation of CoPdP alloys. Fourier-transform infrared spectroscopy was used to probe the Co and Pd sites on the surface. Several Co:Pd ratios were tested in the range of 225–350 °C at a medium pressure of 0.5 MPa. Synergistic effects were observed between Co and Pd, with the alloys showing higher activity than the single metal Pd or Co phosphide catalysts. High selectivity to unsaturated high carbon number products were obtained for the bimetallic phosphide catalysts. [ABSTRACT FROM AUTHOR]

Hematite (α-Fe2O3) is a potential photoanode material for photoelectrochemical (PEC) water splitting, but its short hole diffusion length and low water oxidation kinetics prevent its practical application. In general, the hole transport rate and the water oxidation kinetics could be improved by modifying the oxygen evolution cocatalysts (OECs) in the proper way. In this work, we designed and synthesized a bimetallic phosphides NiCoP nanoparticles (NPs) modified (Ti, Zr)-codoped hematite photoanode (TZ-H) by a facile spin coating method to achieve the uniform and close interface contact of semiconductor/OECs. Under the optimal conditions, the as-prepared photoanode exhibits high and stable PEC performance with a current density of 2.38 mA/cm2 at 1.23 V vs. RHE, which is one of the best performances of noble-metal-free hematite-based photoanodes for water oxidation. Moreover, the surface efficiency of charge separation is improved by NiCoP modification, which is increased from 59% to 91% at 1.23 V vs. RHE and reached nearly 99% at higher potential. This work not only proves that NiCoP NPs are outstanding OECs but also provides a new strategy for the design of noble-metal-free semiconductor/OECs photoanodes with high-quality interface contact. [ABSTRACT FROM AUTHOR]

The high-performance and low-cost NiCoP//WPBC-6 LIC exhibits a high ED of 127.4 ± 3.3 Wh kg−1 and large PD of 18240 W kg−1 as well as excellent cycle stability (capacity retention of 76.4% after 7000 cycles). [Display omitted] • The NiCoP microspheres architecture is synthesized through a hard template and in situ phosphorization process. • The NiCoP microspheres anode material demonstrates prominent specific capacity and rate performance as well as outstanding cycle stability. • The watermelon-peel biomass-derived carbons (WPBCs) were purposefully synthesized and investigated as cathode material to further improve the electrochemical performance of the LICs. • The high-performance NiCoP@Co 2 P//WPBC-6 LIC device presents a high ED of 127.4 Wh kg−1 and a large PD of 18240 W kg−1. Lithium-ion capacitors (LICs) are emerging as one of the most advanced energy storage devices by combining the virtues of both supercapacitors (SCs) and lithium-ion batteries (LIBs). However, the kinetic and capacity mismatch between anode and cathode is the main obstacle to wide applications of LICs. Therefore, the effective strategy of constructing a high-performance LIC is to improve the rate and cycle performance of the anode and the specific capacity of the cathode. Herein, the nickel cobalt phosphate (NiCoP) microspheres anode is demonstrated with robust structural integrity, high electrical conductivity, and fast kinetic feature. Simultaneously, the watermelon-peel biomass-derived carbon (WPBC) cathode is demonstrated a sustainable synthesis strategy with high specific capacity. As expected, the NiCoP exhibits high specific capacities (567 mAh g−1 at 0.1 A g−1), superior rate performance (300 mAh g−1 at 1A g−1), and excellent cycle stability (58 mAh g−1 at 5 A g−1 after 15,000 cycles). The WPBC possesses a high specific surface area (SSA) of 3303.6 m2 g−1 and a high specific capacity of 226 mAh g−1 at 0.1 A g−1. Encouragingly, the NiCoP//WPBC-6 LIC device can deliver high energy density (ED) of 127.4 ± 3.3 and 67 ± 3.8Wh kg−1 at power density (PD) of 190 and 18240 W kg−1 (76.4% capacity retention after 7000 cycles), respectively. [ABSTRACT FROM AUTHOR]

Electrochemical catalytic water splitting process is a potential method for clear hydrogen production. The interfacial electron regulation engineering is an effective path to prepare electrochemical catalysts for water splitting process. Herein, we obtain Ni doping molybdenum-based phosphides with heterojunction interface through a facile method. The acquired Ni doping molybdenum-based phosphides loading on N-doping porous carbon (MoNiP-MoP-PNC) exhibits a high specific surface area (SA), an abundant of porous structure and a electron regulation heterojunction interface. The high SA expose more catalytic sites and the plentiful of pores accelerate the electron/mass transfer, and the electron regulation heterojunction interface can induce the P-orbital electron redistribution to facilitate the adsorption/ desorption (ads/des) of [H] intermediate. The MoNiP-MoP-PNC shows a good catalytic behavior with a low overpotential and an excellent catalytic stability in 1.0 M KOH solution. The synchrotron-radiation results verify the interfacial electron regulation effect that the P -orbital of Mo atom is changed by the adjacent Ni atom and P atom. Meanwhile, density functional theory (DFT) theoretical calculation unmasks that the heterojunction interface can regulate the electron distribution to accelerate the HER. This work indicates a simple route to develop interfacial electron regulation engineering for high effective catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) are regarded as highly efficient electrocatalysts due to highly active surface sites, electrical conductivity, and chemical stability, which result from the high electrocatalytic activity of the M-centers and P-sites. Thus, the aim of our work is to obtain highly efficient TMPs electrocatalysts by a facile and controllable strategy. We used N, S-rich Co/Fe bimetallic metal-organic framework as template to prepare ceramic Co/Fe binary phosphides embedded in N, S, O ternary-doped carbon matrix (CoFeP@NSOC). By means of a facile one-step low-temperature pyrolysis-phosphating approach, the optimized ceramic material CoFeP@NSOC-400 showed remarkable bifunctional electrocatalytic performances in an alkaline electrolyte, which only requires 176 and 240 mV overpotentials to achieve 10 mA cm−2 current density for HER and OER, respectively. Furthermore, when CoFeP@NSOC-400 is loaded on the highly conductive nickel foam (NF) for water splitting, it reaches a current density of 10 mA cm−2 at a low cell voltage of 1.62 V, superior to pure NF and other reported metal-phosphide electrocatalysts, at the same time, CoFeP@NSOC-400 shows negligible performance degradation and a relative current loss of only 4.3% for 40000 s continuous operations. These results indicate CoFeP@NSOC derived by MOFs through pyrolysis-phosphating is an ideal electrocatalysts for energy conversion applications. Nanostructured Co/Fe binary phosphides embedded in N, S, O ternary-doped carbon matrix by facile one-step low-temperature pyrolysis-phosphating approach from a N, S-rich bimetallic MOF to drive water splitting. By adjusting the phosphating temperature, the optimum CoFeP@NSOC-400 exhibits excellent bifunctional electrochemical performances for HER and OER in an alkaline electrolyte. When CoFeP–NSOC-400 is loaded on the foamed nickel for water splitting, a lower voltage 1.62 V is obtained to reach a current density of 10 mA cm−2. This paper proposes a one-step and low-cost phosphating method to obtain nanostructured bimetallic phosphides containing heteroatom doping carbon matrix, showing prominent electrocatalytic performance for water splitting. [Display omitted] • MOFs-derived Co/Fe TMPs embedded in N, S, O ternary-doped carbon matrix. • Co/Fe TMPs were fabricated by one-step low-temperature pyrolysis-phosphating approach. • The optimized TMP is a remarkable bifunctional electrocatalyst for efficient water splitting. [ABSTRACT FROM AUTHOR]

Copper‐nickel phosphides/ graphite‐like phase carbon nitride (Cu3P‐Ni2P/g‐C3N4) composites were obtained through a facile one‐pot in situ solvothermal approach. The coexistence of Cu3P and Ni2P plays an important role in enhancing the catalytic activity of g‐C3N4. The 7 wt% Cu3P‐Ni2P/g‐C3N4 bimetallic phosphide photocatalyst demonstrates the best photocatalytic hydrogen (H2) evolution rate of 6529.8 μmol g−1 h−1, which is 80.7‐fold higher than that of g‐C3N4. The apparent quantum yield (AQE) was determined to be 18.5% at 400 nm over the 7% Cu3P‐Ni2P/g‐C3N4. This in situ growth strategy produced intimate contact interfaces, leading to a significantly promoted separation of charge carriers, and hence strengthened the photocatalytic H2 production. Moreover, the coexistence of Cu3P and Ni2P reduced the overpotential of H2 during the evolution process, further benefiting H2 production. Finally, the photocatalytic enhancement mechanism was proposed and verified by fluorescence and electrochemical analysis. This work provides a low‐cost strategy to synthesize nonprecious bimetallic phosphides/carbon nitride photocatalyst with outstanding H2 production activity. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Herein, a new type of multiwalled carbon nanotube anchored on hierarchically porous metal–organic framework (MOF)‐derived bimetallic phosphide composites (M16‐ZIF‐67‐CNT‐P) is reported, which is calcined from the 16‐nuclear calixarene‐based clusters together with typical ZIF‐67 polyhedra through a stepwise pyrolysis strategy. The as‐obtained M16‐ZIF‐67‐CNT‐P sample possesses large specific surface area, quick ion diffusion, high electrical conductivity, and abundant exposed active sites, which exhibits the highest electrocatalytic capability in comparison with the control counterparts. Meanwhile, this type of nanocomposite possesses a superb anodic oxygen evolution reaction (OER) performance requiring 260 mV for 10 mA cm−2. Overall, MOF‐impregnated clusters–derived M16‐ZIF‐67‐CNT‐P exhibits an efficient water splitting performance. This method can be further extended into other systems of high‐nuclear clusters with MOF materials for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

• Metal-formate frameworks are utilized to prepare hollow structures. • Both synergistic effect between Ni and Co and hollow structures contribute to facilitating the OH− adsorption capability for fast faradaic redox reaction. • NiCoP-2 microcubes deliver enhanced specific capacitance and excellent energy density. Given that combined merits of both compositions and novel structures play important roles in energy storage of electrode materials, we herein use [CH 3 NH 3 ][Ni x Co 1-x (HCOO) 3 ] as self-sacrificed precursors to synthesize structure-controlled hollow nickel cobalt phosphides microcubes. The as-obtained hollow NiCoP-2 displays the highest specific capacity of 629 C g−1 at 1 A g−1 and superior cycling stability with 81.3% capacitance retention at 6 A g−1 after 8000 cycles. Moreover, the asymmetric supercapacitor composed of NiCoP-2 and commercial active carbon (YP-80F) presents the remarkable battery storage performance in terms of outstanding specific capacitance (121.5 F g−1 at 1 A g−1), excellent cycling durability (90.1% capacitance retention after 10,000 cycles) and high energy density of 43.2 Wh kg−1 at a power density of 801.6 W kg−1. The attractive performance can be ascribed to superiority of the transition metal phosphides, hollow structures, as well as synergism between Ni and Co. [ABSTRACT FROM AUTHOR]

Transition metal phosphides are very attractive because of the remarkable performance in energy storage and conversion. Herein, a series of bimetallic phosphides are synthesized through a one-step solid-state reaction. The obtained bimetallic phosphides show outstanding properties as supercapacitor electrode materials. Results show that the incorporation of secondary metal into phosphides tunes composition, electronic structure and then the electrochemical performance. And electrochemical properties are closely associated with the secondary metal content. Notably, the obtained NiCoP shows the best performance with 2011 F g−1 at 1 A g−1. And an asymmetric supercapacitor (ASC) based on NiCoP shows energy density of 47.6 W h kg−1, along with 90.5% of capacitance maintained after 10000 cycles. In addition, the NiCoP also possesses great performance toward hydrogen evolution reaction (HER), which displays the lowest potential of 0.221 V vs. RHE and 0.173 V vs. RHE at 10 mA cm−2 in 0.5 M H 2 SO 4 as well as 1.0 M KOH, respectively. The excellent properties may result from the enhanced electrical conductivity, synergistic effects among metal elements and the increased local electrical dipole. The regulation of electronic structure through introduction of secondary metal atom sheds considerable light on realization and preparation of the bimetallic transition metal compounds as electrode materials. • Electronic structure is related to the secondary metal content. • NiCoP shows outstanding performance with 2011 and 1461 F g−1 at 1 and 10 A g−1. • Excellent property is due to increased local electrical dipole and conductivity. • NiCoP holds promise as outstanding electrode material in asymmetric supercapacitor. • NiCoP shows excellent electrocatalytic performance toward HER in both acidic and alkaline solutions. [ABSTRACT FROM AUTHOR]

Nanostructured transition-metal phosphides (TMPs) have recently emerged as a new family of non-noble-metal catalysts to drive water splitting due to their unique electronic and redox properties. However, most progress focused on developing mono-metal phosphide nanostructures. In this work, a facile template-based method and low-temperature phosphorization process are proposed to fabricate self-supported Ni-based bimetallic phosphide encapsulated in amorphous carbon by using metal-organic framework (MOF) as the precursor and three-dimensional nickel foam (NF) as the support, which is termed as Ni 2 P-Co 2 P@C/NF. This composite demonstrates remarkable electrocatalytic activities towards both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolyte (1 M KOH, pH 13.6), affording low overpotentials of 290 and 167 mV to deliver the current density of 50 mA cm−2 for OER and HER, respectively, preceding the majority of recently reported MOFs-derived TMPs. This excellent performance is considered as the results of its large catalytic surface area, concerted synergy from composited structure as well as the increased electrical conductivity. [ABSTRACT FROM AUTHOR]

Large-scale electrolysis of water to produce hydrogen is an effective way to obtain clean renewable energy. The first-row transition-metal-based oxygen evolution reaction (OER) catalysts with high activity have been developed to replace the noble-metal catalysts, e.g., RuO 2 and IrO 2. In the work reported in this paper, we developed the Ni–Fe Prussian-blue analog (PBA) on the Ni foam surface (PBA/NF) via an in situ electrodeposition method and transferred the PBA/NF into bimetallic phosphides (NiFeP x /NF) through the phosphidation process as highly active OER electrocatalysts in alkaline medium. The in situ electrodeposition method could not only precisely control the nucleation and growth processes of PBA on the surface of nickel foam, as well as the purity, structures, and morphologies of the deposits obtained, but also provide sufficient adhesive force between catalysts and Ni foam substrates without further use of poorly conductive binder material, which guaranteed robust electrode stability. When applying for OER, NiFeP x /NF presented excellent catalytic activity. Upon screening a wide electrodeposition time range, results demonstrate that NiFeP x -80/NF (deposition time 80 min) possessed the best OER catalytic activity with only 224 mV to deliver a current density of 10 mA cm−2 as well as a Tafel slope of 29 mV dec−1 in 1 M KOH, which shows that the use of electrodeposition methods to directly grow PBA nanomaterials on conductive substrates may be an effective method for the preparation of multifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The uniform bimetallic CoFeP hollow microspheres have been synthesized. • The hollow structure of CoFeP is helpful to increase the exposed actives. • The bimetallic composites can provide the better intrinsic activity. • The synergistic effect from bimetallic phosphides contributes to the enhanced performances. Abstract The ingenious design and synthesis of bifunctional electrocatalysts with high activity and robust stability for hydrogen evolution reaction and oxygen evolution reaction (HER and OER) is desirable and challenging. Herein, bimetallic phosphides CoFeP with hollow microspheres structure has been synthesized through a facile gas phosphorization as bifunctional electrocatalyst for overall water splitting. SEM and TEM demonstrate the formation of uniform hollow microspheres of CoFeP. The hollow structure of CoFeP is helpful to increase the exposed actives and the larger contact surface with electrolyte. The bimetallic composites can provide the better intrinsic activity. Compared with single metallic phosphides CoP and FeP, the obvious enhancement of electrocatalytic performances of CoFeP can be observed. The electrochemical results show that the bimetallic CoFeP hollow microspheres only have the lower overpotential of 177 and 350 mV (vs. RHE) to drive a current density of 10 mA cm−2 for HER and OER, respectively. The reasons may be due to the hollow nanostructure and the synergistic effect from bimetallic phosphides. This work provides a facile and effective way to design excellent phosphides electrocatalysts for water splitting based on gas phosphorization of bimetallic oxides precursors. [ABSTRACT FROM AUTHOR]

A highly active bi-functional electrocatalyst towards both hydrogen and oxygen evolution reactions is critical for the water splitting. Herein, a self-supported electrode composed of 3D network nanostructured NiCoP nanosheets grown on N-doped carbon coated Ni foam (NiCoP/NF@NC) has been synthesized by a hydrothermal route and a subsequent phosphorization process. As a bifunctional electrocatalyst, the NiCoP/NF@NC electrode needs overpotentials of 31.8 mV for hydrogen evolution reaction and 308.2 mV for oxygen evolution reaction to achieve the current density of 10 mA∙cm-2 in 1 mol·L-1 KOH electrolyte. This is much better than the corresponding monometal catalysts of CoP/NF@NC and NiP/ NF@NC owing to the synergistic effect. NiCoP/NF@NC also exhibits low Tafel slope, and excellent long-term stability, which are comparable to the commercial noble catalysts of Pt/C and RuO2. [ABSTRACT FROM AUTHOR]

Abstract: An integrated, free‐standing, and binder‐free type of flexible anode electrode is fabricated from numerous holey‐structured, 2D nickel‐based phosphide nanosheets connected with carbon nanotubes. This electrode architecture can not only uniformly disperse the nanosheets throughout the whole electrode to avoid aggregation or detachment, but also provide an ideal sodium ion and electrolyte diffusion and penetration network with high electronic conductivity. Meanwhile, bimetallic phosphide formation by introducing secondary metal species will lead to a synergistic effect to modify the electrochemical properties. Due to the excellent compositional and structural characteristics of this electrode, it delivers superior performance. This designed flexible anode with Ni1.5Co0.5Px nanosheets demonstrates a reversible capacity of 496.4 mAh g−1 at 0.5 C and a good rate capacity of 276.1 mAh g−1 at 8 C. Meanwhile, this connected integrated network woven from carbon nanotubes can effectively restrain volumetric expansion and shrinkage, and affect the conversion reaction products formation as well, from large‐sized microspheres to film structure, which is primarily credited with the improvement in electrochemical performance. This work may open up a new path for the synthesis of morphology‐controlled phosphides and promote the further development of flexible devices. [ABSTRACT FROM AUTHOR]

In this paper, the preparation and electrochemical capacitive performance of hollow urchin-like Ni 2 P/CoP (HU Ni 2 P/CoP) bimetallic phosphides have been reported. Electrochemical measurements deliver a high specific capacity of 1038 F g −1 at a current density of 1 A g −1 , and achieve the good capacitance retention of 91% after 3000 cycles at 20 A g −1 , indicating HU Ni 2 P/CoP bimetallic phosphides can be used as the novel electrode materials for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) are widely used as supercapacitor energy storage materials due to their abundant valence and high theoretical capacity, but their poor electrical conductivity and low active material utilization lead to low actual capacity and slow kinetics. Herein, we demonstrate the excellent electrochemical properties of sulfur-doped Co 2 P@Ni 2 P heterojunction materials prepared using a combination of hydrothermal, ion-exchange and low-temperature annealing approaches. For sulfur-doped Co 2 P@Ni 2 P, hollow core-shell microstructures increase the number of electroactive sites and provides a shortcut for electron transport, while sulfur doping promotes the transfer and rearrangement of interfacial charge from Co 2 P to Ni 2 P, optimizing the redox ability of the active component. In addition, the S doping and the highly electrochemically active nickel-cobalt phosphide synergistically accelerate the charge transfer, which leads to fast reaction kinetics. Therefore, the obtained S-Co 2 P@Ni 2 P exhibits an optimal specific capacity of 1200 C g−1 at 1 A g−1 and excellent rate performance. Furthermore, when combined with activated carbon (AC) for hybrid supercapacitor (HSC), the S-Co 2 P@Ni 2 P//AC device shows an excellent energy density of 41.5 Wh kg−1 and a high-capacity retention of 93 % after 15,000 cycles. This work provides a novel approach for the exploration of high-performance and stable phosphorus-based battery-like supercapacitor materials. Synthesis of S-Co 2 P@Ni 2 P hollow core-shell heterogeneous materials by a combining hydrothermal reaction, ion exchange and low-temperature phosphating. [Display omitted] • Hollow core-shell S-Co 2 P@Ni 2 P heterojunction materials were synthesized. • Hollow core shell structure buffers volume stress shocks. • The possesses abundant heterogeneous interfaces and active sites. • S-Co 2 P@Ni 2 P exhibits excellent specific capacity and cycling performance. [ABSTRACT FROM AUTHOR]

A series of supported Ni-Mo-P alloy catalysts was studied for the catalytic hydrodeoxygenation (HDO) of the cyclic five-membered ester γ-valerolactone (GVL-C 5 H 8 O 2 ) as a model compound for pyrolysis oil. Alloy formation in Ni-Mo-P was indicated by X-ray diffraction analysis and X-ray absorption near-edge spectroscopy, which showed systematic shifts with composition. The number of active sites of each metal species was estimated by factor analysis combining CO-uptake measurements and infrared (IR) spectra of adsorbed CO. It was found that the catalytic activity followed the order: Ni 2 P/MCM-41 > NiMo(3:1)P/MCM-41 > NiMo(1:1)P/MCM-41 ≅ (Ni 2 P + MoP)/MCM-41 > NiMo(1:3)P/MCM-41 > MoP/MCM-41, whereas the normalized turnover frequency based on Ni sites were similar for all the catalysts, while retaining the same order. It is concluded that adjacent surface Ni atoms are the main active sites involved in the rate-determining step (rds). The Mo-containing catalysts produced more 1-pentanol and C5 hydrocarbons than Ni 2 P/MCM-41, indicating that while the exposed Ni sites governed catalytic activity, Mo sites controlled the selectivity to C5 hydrocarbons. Thus, steps following the rds were influenced by Mo sites, leading to preferences for different reaction pathway during the HDO of γ-valerolactone. The study reveals that the catalytic behavior of NiMoP catalysts can be tuned by the relative proportion of Ni and Mo sites. [ABSTRACT FROM AUTHOR]

Cobalt-based bimetallic phosphide encapsulated in carbonized zeolitic imadazolate frameworks has been successfully synthesized and showed excellent activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory calculation and electrochemical measurements reveal that the electrical conductivity and electrochemical activity are closely associated with the Co2P/CoP mixed phase behaviors upon Cu metal doping. This relationship is found to be the decisive factor for enhanced electrocatalytic performance. Moreover, the precise control of Cu content in Co-host lattice effectively alters the Gibbs free energy for H* adsorption, which is favorable for facilitating reaction kinetics. Impressively, an optimized performance has been achieved with mild Cu doping in Cu0.3Co2.7P/nitrogen-doped carbon (NC) which exhibits an ultralow overpotential of 0.19 V at 10 mA cm-2 and satisfying stability for OER. Cu0.3Co2.7P/NC also shows excellent HER activity, affording a current density of 10 mA cm-2 at a low overpotential of 0.22 V. In addition, a homemade electrolyzer with Cu0.3Co2.7P/NC paired electrodes shows 60% larger current density than Pt/RuO2 couple at 1.74 V, along with negligible catalytic deactivation after 50 h operation. The manipulation of electronic structure by controlled incorporation of second metal sheds light on understanding and synthesizing bimetallic transition metal phosphides for electrolysis-based energy conversion. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) derived materials are widely concerned due to their diversity, porous structures, multiple active sites of metal-organic frameworks, as well as the facile synthesis process. In this work, the Cu–PBAs grow in-situ on Titanium (Ti) net, and then the Cu 3 P and Fe 2 P materials (Cu–Fe–P/TiN) is prepared with subsequent phosphorization, which can be used as binder-free and conductive agent-free anode for sodium-ion batteries. And the Cu–Fe–P is closely linked with Ti net to form a conductive network by regular rod-like particles, which contributes to the excellent electrochemical performance. The Cu–Fe–P/TiN can deliver a high reversible capacity of more than 180 mAh g−1 at 50 mA g−1, and achieve a capacity retention rate of 70% after 100 cycles. At areal current density of 1 mA cm−2, the reversible capacity of the Cu–Fe–P/TiN electrode is 1.6 mAh cm−2. The reversible transformation and sodium storage mechanism are further revealed by in-situ characterizations. [Display omitted] • The Cu–Fe–P/TiN is obtained by phosphating with Cu-based PBA grown on the Ti net. • The Cu–Fe–P/TiN anode is binder-free and conductive agent-free. • The Cu–Fe–P/TiN anode displays excellent electrochemical performances for SIBs. • The reversible transformation of Cu–Fe–P/TiN is confirmed by in-situ technologies. [ABSTRACT FROM AUTHOR]

• Amorphous Ni-Ru bimetallic phosphide composites were synthesized. • The total acidity exhibits a linear correlation with the hydrogenolysis yield. • High hydrogenolysis yield is achieved without excessive hydrogenation. • 2D-NMR HSQC analysis of dealkaline lignin and residue. Gas-phase SiO 2 -supported amorphous Ni-Ru bimetallic phosphide composite catalysts (NiRuP/SiO 2) are prepared in this study. Using diphenyl ether as a lignin-related model compound, the reactivity of NiRuP/SiO 2 in the catalytic hydrogenolysis of a 4– O –5-type linkage is investigated under mild conditions. The molar ratios of n Ni/ n Ru and n P/ n M have a significant influence on the acidic properties of the bimetallic phosphides. The total acidity exhibits a strong linear correlation with the hydrogenolysis yield of diphenyl ether. Among all the catalysts, the Ni 5 RuP 2 /SiO 2 catalyst shows high catalytic activities for the hydrogenolysis of diphenyl ether without excessive hydrogenation and is introduced to depolymerize lignin. Furthermore, 2D-HSQC-NMR spectroscopy analysis revealed that Ni 5 RuP 2 /SiO 2 exhibited high activity for C–O cleavage. The predominant hydrogenolysis products from lignin are higher value-added chemicals. The findings of this work are beneficial to the biorefinery industry and provide an alternative method to make better use of lignin. [ABSTRACT FROM AUTHOR]

In this study, bimetallic phosphides were reported to be novel, efficient, and stable activators of peroxymonosulfate (PMS). CoFe 2 P x was synthesized by phosphorization of CoFe 2 O 4 and applied in PMS activation for sulphachloropyridazine sodium (SCP) degradation. The SCP removal reached up to 94.2% in 30 min, with a reaction rate of 0.090 min−1. Particularly, CoFe 2 P x exhibited much lower cobalt ion leaching (0.082 mg L−1) than the reported cobalt-containing catalysts, due to the more intimate Co-Fe interaction and the surrounding of metals by phosphorus. Different from the free radical pathway in CoFe 2 O 4 /PMS system, a radical-nonradical coupling process was detected in CoFe 2 P x /PMS system, which was confirmed by quenching tests, electron paramagnetic resonance (EPR) measurements, and transformation intermediate analyses. Moreover, CoFe 2 P x demonstrates favorable durability for PMS activation and potential practicability for realistic wastewater treatment. This work provides new insights for rational design and mechanism exploration of transition-metal phosphides (TMPs) in the environmental catalysis field. [Display omitted] • Novel bimetallic phosphide, CoFe 2 P x , activated PMS efficiently. • The Co leaching amount was much lower than those in previous studies. • The special crystal lattice of CoFe 2 P x was responsible for the reduced Co leaching. • In addition to SO 4 •− and •OH, 1O 2 and O 2 •− were detected in CoFe 2 P x /PMS system. • Pyridazinyl ring-opening products were identified during SCP degradation. [ABSTRACT FROM AUTHOR]

Rational design and exploitation of efficient and inexpensive catalysts for water electrolysis are highly desired, yet very challenging. Herein, for the first time, we report a nanostructured catalyst of nickel phosphides-ruthenium phosphides self-supported on nickel foam (Ni 2 P-Ru 2 P/NF) through an in situ growth-phosphorization process. As expected, by virtue of prominent intrinsic activity, rich electrochemically active sites, and high electronic conductivity, the resultant Ni 2 P-Ru 2 P/NF exhibits enhanced electrocatalytic behavior for the oxygen evolution reaction and hydrogen evolution reaction, which delivers low overpotentials of 160 and 101 mV at 10 mA cm 2 in alkaline media, respectively. Remarkably, the Ni 2 P-Ru 2 P/NF can dramatically accelerate full water splitting with an ultralow cell voltage of 1.45 V at 10 mA cm−2, which far exceeds the benchmark Pt-C/NF//RuO 2 /NF (1.64 V) and ranks among the best electrocatalysts previously reported. A high-efficiency bifunctional electrocatalyst for the oxygen evolution reaction and hydrogen evolution reaction was designed by constructing the Ni 2 P-Ru 2 P heterointerfaces on nickel foam. Impressively, the resultant catalyst exhibits outstanding catalytic performance toward overall water splitting. [Display omitted] • Self-supported Ni 2 P-Ru 2 P/NF with abundant artificial heterointerfaces is successfully synthesized in situ. • Unique 3D architectures with superhydrophilicity provide large surface area and rich exposed sites. • Ni 2 P-Ru 2 P/NF shows enhanced catalytic performance for OER and HER. • An ultralow cell voltage (1.45 V) and about 100% Faradaic yield toward over water splitting. [ABSTRACT FROM AUTHOR]

The preparation, characterization, and catalytic activity of supported metal phosphides are reviewed. Reduction of metal compounds together with phosphate is a convenient method to prepare metal phosphides, but requires high temperature. Reduction with phosphite, hypophosphite, or phosphine and the plasma reduction of phosphate can be carried out at lower temperatures, which leads to smaller metal phosphide particles and more active catalysts. Organometallic routes allow the separate synthesis of metal phosphide nanoparticles, which have to be added to the support in a second step. LEED, STM, XPS, and DFT studies have shown that the surfaces of NiP reconstruct to P-rich surfaces. The investigation of metal phosphides as catalysts for hydrotreating reactions continues to be a topic of considerable research with recent advances realized in using bimetallic and noble metal phosphides to achieve high activities and tailored selectivities. Finally, hydrodeoxygenation catalysis over metal phosphides is a growing area of research given the need to develop catalysts for upgrading biomass to transportation fuels. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highly efficient and robust bimetallic NiCoP@PNCNF catalysts for water splitting reaction are profited from unique macro-structural designs and micro-electronic/geometric modifications. [Display omitted] • Ultra-small NiCoP embedded in PNCNF were fabricated via electrospinning method. • The optimal NiCoP@PNCNF exhibits excellent performance both for HER and OER. • Water splitting results display outstanding performance and Faraday efficiency. Integrating the unique metalloid behaviour of monometallic phosphides and modified local electronic/geometric structures of active sites, bimetallic phosphides have emerged as promising candidates for water splitting reaction, but they are still synthesized by toxic, corrosive, and high-temperature methods, which inevitably resulted in an increase of particle size and the decrease of catalytic activity area. Herein, the ultra-fine bimetallic NiCoP catalysts in-situ embedded in P, N-codoped carbon nanofibers (NiCoP@PNCNF) were successfully fabricated via a facile electrospinning method with the help of phytic acid. Profiting from the unique macro-structural design and micro-electronic/geometric modification, as-prepared NiCoP@PNCNF catalysts exhibited excellent catalytic performance both for HER (η 10 = 98 mV) and OER (η 10 = 260 mV) in terms of the low overpotential and robust stabilities in alkaline solution. Meanwhile, XAFS analysis further demonstrated that the remarkable catalytic performance not only attributed to the introduction of heteroatom-doped carbon fibers as their improvements in the corrosion resistance, anti-agglomeration abilities, and conductivity, but also benefited from the local electronic/geometric structure alternations as the strong synergic effects between Ni/Co and P atoms. For practical application, the water splitting performance based on NiCoP@PNCNF electrodes was also investigated and exhibited a lower splitting potential (E J=10, 1.645 V) over long-term stability tests. These insightful findings undoubtedly shed light on the design and fabrication of cost-effective and robust bifunctional transition-metal phosphides electrocatalysts. [ABSTRACT FROM AUTHOR]

• Confinement effect induced by PPA supramolecular network as well as electrospinning. • In-situ carbonization and phosphating of PAN and PA are environmentally friendly. • Bimetal phosphide alters electronic structure and improves the interface dynamics. [Display omitted] Research of highly dispersed transition metal phosphides (TMPs)-based catalysts for electrocatalytic hydrogen evolution is of great significance in the area of renewable energy. Herein, the high dispersion of FeNiP nanoparticles on N, P-doped electrospun carbon fibers was realized via the confinement effect induced by phytic acid (PA) and polyacrylonitrile (PAN), as well as electrospinning technique. PA and PAN were used as ligand for coordinating transition metal (TM) ions and carbon sources, respectively. In addition, the nucleophilic addition reaction between PA and PAN resulted in the cyclization of PAN and the further formation of a supramolecular network. Besides, the chelating ability of PA to TM ions was also modulated. Benefitting from the confinement effect, the optimized FeNiP/NPC800 exhibit good hydrogen evolution reaction (HER) activities for achieving a current density of 10 mA cm−2 at an overpotential of 277 mV in 0.5 M H 2 SO 4. [ABSTRACT FROM AUTHOR]

The construction of efficiently non-noble metal bifunctional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is a major challenge for renewable energy generation. Here, considering the synergistic effect of differently metal sites and excellent electrocatalytic activities of bimetallic phosphides, the hybrids of NiCo bimetallic phosphides (NiCo–P) are prepared by one-step phosphorization of NiCo metal-organic frameworks (NiCo-BDC) as bifunctional electrocatalysts for water splitting. Benefiting from the unique porous structure and synergistic effect of Ni 2 P and Co 2 P in bimetallic phosphides system, Ni1Co1–P hybrid exhibits outstanding electrocatalytic activities for both OER and HER, with small overpotentials 343 mV (OER) and 169 mV (HER) at a current density of 10 mA cm−2 in alkaline conditions, respectively, which compares to monometallic phosphides (Ni–P and Co–P) and Ni–P + Co–P sample, illustrating the existence of Ni 2 P/Co 2 P interface as an essential requirement to achieve the synergistic effect and the improved catalytic activities in NiCo–P system. This work provides a general strategy to design more efficient multicomponent electrocatalysts. Image 1 • The bimetallic phosphide Ni1Co1–P hybrid was prepared with simple ultrasonic stripping and phosphorization methods. • Ni1Co1–P with unique hierarchical porous structure and Ni 2 P and Co 2 P phases wrapped in ultrathin carbon film. • Ni1Co1–P hybrid unique structure endows handy ion diffusion path, enhanced conductivity and synergistically active sites. • Ni1Co1–P exhibited excellent activity for OER and HER in alkaline solution, this is favorable for practical application. [ABSTRACT FROM AUTHOR]

• 3D N-enriched holey carbon layers encapsulated bimetallic phosphides was synthesized. • CoNiP@CN/NF was obtained by a in situ electrodeposition, pyrolysis and phosphorization. • The bifunctional electrocatalyst exhibited better performance in both HER and OER. • Require only 1.59V@30 mA cm−2 in alkaline solution with robust durability for overall water splitting. Cost-effective transition metal-carbon-based hybrids have been widely dedicated to water splitting. Herein, a new three dimensional N-enriched holey carbon layers encapsulated bimetallic phosphides (CoNiP@CN) was synthesized by in situ growth, pyrolysis and phosphorization of CoNi mixed zeolite imidazole frameworks (ZIFs)@ZIF-8 films on Ni foam. CoNiP@CN/NF exhibited smaller overpotentials, lower charge transfer resistance and considerable stability for electrocatalysis. The better performance was attributed to the high conductivity of bimetallic phosphides and N-doped porous carbon, the maximum utilization of active sites on 3D conductive substrate and the protection of bimetallic phosphides by N-doped carbon layers. As an integrated high-performance non-noble electrocatalyst for overall water splitting, the CoNiP@CN/NF requires only 1.59 V@30 mA cm−2 in alkaline solution, which is comparable to many other non-noble metal catalysts. This work highlights the construction highly efficient transition metal-carbon-based electrocatalyst derived from well-defined ZIF precursor, promoting the development of low-cost non-noble metal hybrids in energy chemistry. [ABSTRACT FROM AUTHOR]

The key issue of developing the metal phosphides based electrode material is to explore the green synthesis approach and maintain the structural stability during practical applications. Herein, we report a facile electrodeposition approach combined with subsequent thermal treatment to grow Fe–Co–P on the porous carbon membrane with Magnolia leaves as precursor (Fe–Co–P/C). The three-dimensional porous carbon frameworks as substrate provide superior electrical conductivity for Fe–Co–P/C electrodes. The strong coupling between Fe–Co–P and porous carbon framework keeps the stable electron and ion transport channels for the electrode materials in the sodium ion batteries and oxygen evolution reactions. The Fe–Co–P/C as anode materials for sodium ion batteries deliver a high discharge capacity of 464 mAh g−1 at 0.1 A g−1. After 500 cycles at the current density of 0.5 A g−1, the capacity of the electrode still retain 293 mAh g−1, which is attributed to the porous carbon framework to confine the Fe–Co–P in the composites and prevent the Fe–Co–P nanoparticles from aggregating. On the other hand, the Fe–Co–P also exhibit high-efficient performance for oxygen evolution reaction with the overpotential of 151 mV to reach the current density of 10 mA cm−2, and the Tafel slope of 77.78 mV dec−1 in 1.0 M KOH. Our research provides a unique carbon substrate material with hierarchical nanostructure and new design stagey for bimetallic phosphide based electrode for sodium ion batteries and electrocatalytic oxygen evolution reactions. Image 1 • Fe–Co–P/C integrated electrodes were synthesized by electrodeposition. • The Fe–Co–P/C exhibits enhanced sodium storage and high stability for sodium ion batteries. • Synergistic effects of Fe and Co in Fe–Co–P/C could promote the electrochemical activity for OER. [ABSTRACT FROM AUTHOR]

It is a huge challenge for exploiting new photocatalysts with low‐cost cocatalysts in place of precious metals to realize high‐efficiency H2 production from water. Herein, a new photocatalyst with a high H2 production activity is prepared via modification of bimetallic manganese cobalt phosphide (Mn0.67Co1.33P) nanodots on graphitic carbon nitride (g‐C3N4). Moreover, the largest H2 production rate of 113.1 μmol h−1 is obtained over the Mn0.67Co1.33P/g‐C3N4‐5 sample, which is about 2.75 times than that of Pt/g‐C3N4‐5 (41.2 μmol h−1). The high‐performance H2 production suggests page a page down that the modification effect of Mn0.67Co1.33P nanodots improves the visible harvest ability and separation efficiency of charge carriers. A typical example to improve the photocatalytic H2 production performance by fabricating heterostructures using bimetallic phosphide to modify graphitic carbon nitride is provided. [ABSTRACT FROM AUTHOR]

The electrochemical splitting of water provides an attractive method for the production of hydrogen fuels. Unfortunately, the slow kinetics of oxygen evolution (OER) on the anode side of the electrolyzer hinders the efficient and large-scale hydrogen production. In this study, starting from metal-organic frameworks (MOFs), a series of bimetal phosphides Co x Fe 1-x P (x = 0.33, 0.50, 0.66, 0.75 and 0.80) were synthesized by low-temperature phosphidiation of corresponding MOFs precursors. The as-prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Studies indicate that the proportion of cobalt and iron elements make a big differences on the structure of the materials. Benefiting from the porous structure and large specific area of the MOFs precursors, as well as the synergistic effect between Co and Fe elements, the as-synthesized Co 0.66 Fe 0.33 P shows superior electrocatalytic performances and outstanding stability toward OER in alkaline solution., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Bimetallic phosphides have attracted research interest for their synergistic effect and superior electrocatalytic activities for electrocatalytic water splitting. Herein, a MOF-derived phosphorization approach was developed to produce Ni 2 P-CoP bimetallic phosphides as bifunctional electrocatalysts for both hydrogen and oxygen evolution reactions (HER and OER). Ni 2 P-CoP shows superior electrocatalytic activities to both pure Ni 2 P and CoP toward HER and OER, revealing a strong synergistic effect. High-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy elemental mapping analysis show that, in the sample Ni 2 P-CoP, the Ni 2 P and CoP nanoparticles with an average particle size 10-20 nm were mixed closely on the nanoscale, creating numerous Ni 2 P/CoP interfaces. By comparison with the sample Ni 2 P+CoP, in which seldom Ni 2 P/CoP interfaces exist, we documented that the Ni 2 P/CoP interface is an essential prerequisite to realize the synergistic effect and to achieve the enhanced electrocatalytic activities in Ni 2 P-CoP bimetallic phosphides. This finding is meaningful for designing and developing bicomponent and even multicomponent electrocatalysts.