FeP Nanoparticles Research Articles

FeP nanoparticles derived from metal-organic frameworks/GO as high-performance anode material for lithium ion batteries

Double carbon coated FeP composite (FeP@NC@rGO) was in situ fabricated via the phosphorization process of the as-prepared Prussian blue@graphene oxide (PB@GO) precursor. The FeP nanocrystals were successfully embedded in the nitrogen-doped porous carbon matrix. When used as the anode for lithium ion batteries (LIBs), the FeP@NC@rGO anode shows superior lithium storage properties, delivering a high specific capacity of 830 mA h g−1 after 100 cycles at 100 mA g−1 and excellent rate capability of 359 mA h g−1 at 5 A g−1. The outstanding performance mainly ascribes to the synergistic effect of the double carbon coating and porous structure design. The introduction of porous carbon and graphene coating on FeP nanoparticles greatly enhance the electronic conductivity of the active material and well accommodates the large volume variation of FeP during the cycling process.

FeP Nanocrystals Embedded in N-Doped Carbon Nanosheets for Efficient Electrocatalytic Hydrogen Generation over a Broad pH Range

Recently, great attention has been spent in the exploitation of stable and highly efficient nonprecious metal-based catalysts that can be applied to energy conversion techniques by electrocatalytic reaction. Transition metal phosphides (TMPs) are promising and intriguing candidates for the hydrogen evolution reaction (HER) as well as other energy conversion technologies. Here we present a facile sol–gel route aimed at synthesizing FeP nanocrystals embedded in N-doped carbon nanosheets (FeP/NCNSs). The obtained nanocomposite exhibits excellent hydrogen generation activity, achieving 10 mA cm–2 at relatively low overpotential (114 mV) in acidic electrolyte (0.5 M H2SO4). In the respect of structural integrity, the N-doped carbon layer could protect the FeP nanocrystals from acidic degradation, thus endowing the hybrid with superior durability to the bare FeP nanoparticles during long-term operation. Furthermore, the as-synthesized electrocatalyst also exhibits high catalytic activity and remarkable cyclabil...

Co/Fe-bimetallic organic framework-derived carbon-incorporated cobalt–ferric mixed metal phosphide as a highly efficient photocatalyst under visible light

A new bimetallic Co/Fe-MOF was synthesized and phosphatized to produce a visible-light-active Co/Fe binary metal phosphide embedded in a mesoporous carbon matrix (denoted by CoP/Fe2P@mC). The results of X-ray diffraction and photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy reveal the formation of CoP and Fe2P nanoparticles together with the Co and Fe metallic state. Combining the high electron–hole separation rate of Fe2P@mC, fast electron transfer of CoP@mC, and the strong adsorption of mesoporous carbon, the as-prepared CoP/Fe2P@mC catalyst exhibits substantially enhanced photocatalytic activity toward rhodamine B (RhB) degradation under visible light irradiation. Visible light harvesting efficiency is enhanced by the suitable bandgap structure of the CoP/Fe2P@mC photocatalyst. Moreover, the possible photocatalytic mechanism of CoP/Fe2P@mC toward RhB degradation was proposed on the basis of radical trapping and electron spin resonance results. This finding illustrates a potential utilization of bimetallic MOF-derived metal phosphide as a photocatalyst to remove dye pollutants in the environment.

Hierarchically Porous Carbon Nanofibers Encapsulating Carbon‐Coated Mini Hollow FeP Nanoparticles for High Performance Lithium and Sodium Ion Batteries

AbstractMetal phosphides are appealing candidates for lithium and sodium ion batteries due to their moderate discharge plateau, relatively low polarization and impressive theoretical capacity. Unfortunately, the poor capacity retention and limited cycle life are still big problems as for other phase‐transformation‐type anode materials. Herein, we report a novel one‐dimensional hierarchical material, consisting of carbon‐coated mini hollow FeP nanoparticles homogeneously encapsulated in porous carbon nanofibers (denoted as M‐FeP@C) through a low temperature phosphidation method. The M‐FeP@C hybrid nanofibers deliver high specific capacity, long cycling life stability (542 mAh g−1 after 300 cycles at 1 A g−1) and excellent rate capability for half and full lithium‐ion batteries. In addition, the M‐FeP@C hybrid nanofibers show 474 mAh g−1 after 100 cycles at 0.1 A g−1 as an anode for sodium ion batteries. The outstanding electrochemical performance of the M‐FeP@C hybrid nanofibers for both lithium and sodium storage can be attributed to the advantageous embedding architecture between the mini hollow FeP nanoparticles and double carbon layers scaffold, which offer not only a continuous conducting framework and nanoporous channels for efficient diffusion and transport of ions/electrons, but also provide enough voids to alleviate the volume changes during cycling.

Bifunctional porous iron phosphide/carbon nanostructure enabled high-performance sodium-ion battery and hydrogen evolution reaction

Transition metal phosphides, such as iron phosphide (FeP), have recently been studied as promising high performance active materials for sodium-ion batteries (SIBs) and hydrogen evolution reaction (HER) due to their excellent energy storage and conversion capabilities. To achieve long cycle lifetime, high rate sodium storage performance and stable HER reactivity, porous FeP/C nanostructures have been designed and synthesized through low temperature phosphorization of the Metal-Organic Framework (MOF) nanostructure. The resulting FeP/C composite consists of highly porous nanocubic structure with FeP nanoparticles distributing the carbon scaffolding, showing high surface area and small pore size distribution. This unique nanostructure enables fast and efficient electrons/ions transportation, and provides abundant reactive sites uniformly distributing the highly-ordered MOF-derived nanocubes. Benefitting from the unique porous structure, the FeP/C nanocubes exhibit remarkable sodium storage performance in terms of high capacity (410 mA h g−1, 100 mA g−1), excellent rate capacity (up to 1 A g−1) and long cycle life (> 200 cycles). The electrochemical reaction mechanisms of the FeP/C composite upon sodiation/desodiation are investigated in detail via ex-situ XRD, SEM and TEM methods, which show that the sodium storage in FeP is based on both the intercalation/conversion reactions. In addition, FeP/C as HER electrodes maintain its reactivity for at least 40 h and exhibit an low onset overpotential of 80 mV and a low Tafel slope of 40 mV dec−1. These results reveal the sodium storage mechanism of FeP and suggest that the MOF-derived FeP/C composite is a promising candidate for high-performance SIBs and HER electrode material.

Triphenyl Phosphite as the Phosphorus Source for the Scalable and Cost-Effective Production of Transition Metal Phosphides

Transition metal phosphides have great potential to optimize a number of functionalities in several energy conversion and storage applications, particularly when nanostructured or in nanoparticle form. However, the synthesis of transition metal phosphide nanoparticles and its scalability is often limited by the toxicity, air sensitivity, and high cost of the reagents used. We present here a simple, scalable, and cost-effective “heating up” procedure to produce metal phosphides using inexpensive, low-toxicity, and air-stable triphenyl phosphite as source of phosphorus and chlorides as metal precursors. This procedure allows the synthesis of a variety of phosphide nanoparticles, including phosphides of Ni, Co, and Cu. The use of carbonyl metal precursors further allowed the synthesis of Fe2P and MoP nanoparticles. The fact that minor modifications in the experimental parameters allowed producing nanoparticles with different compositions and even to tune their size and shape shows the high potential and vers...

Boosting the Sodiation Capability and Stability of FeP by In Situ Anchoring on the Graphene Conductive Framework

AbstractMetal phosphides (MPs) have emerged as a new class of high‐capacity and low‐cost anodes for sodium‐ion batteries (SIBs). In order to buffer the volume change during the sodiation process and improve the conductivity, we synthesized a porous composite made of FeP nanoparticles uniformly anchored on 3D reduced graphene oxide structure (FeP@rGO) by a low‐temperature chemical solution deposition method with subsequent phosphorization and thermal reduction processes. Electrochemical characterization indicated that the FeP@rGO composite nanostructured anode delivers an attractive reversible capacity up to 366.6 mAh g−1 with superior cycling stability (388.8 mAh g−1 after 250 cycles) and high Coulombic efficiency (>99%), which is among the previously reported high performance transition MPs‐based SIBs anode materials.

FeP nanoparticles: a new material for microwave absorption

FeP nanoparticles, fabricated through a facile thermal phosphorization process, have displayed impressive microwave absorption performance with tunable frequency and large reflection loss (RL) values.

From an Fe2P3 complex to FeP nanoparticles as efficient electrocatalysts for water-splitting.

In large-scale, hydrogen production from water-splitting represents the most promising solution for a clean, recyclable, and low-cost energy source. The realization of viable technological solutions requires suitable efficient electrochemical catalysts with low overpotentials and long-term stability for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) based on cheap and nontoxic materials. Herein, we present a unique molecular approach to monodispersed, ultra-small, and superiorly active iron phosphide (FeP) electrocatalysts for bifunctional OER, HER, and overall water-splitting. They result from transformation of a molecular iron phosphide precursor, containing a [Fe2P3] core with mixed-valence FeIIFeIII sites bridged by an asymmetric cyclo-P(2+1) 3- ligand. The as-synthesized FeP nanoparticles act as long-lasting electrocatalysts for OER and HER with low overpotential and high current densities that render them one of the best-performing electrocatalysts hitherto known. The fabricated alkaline electrolyzer delivered low cell voltage with durability over weeks, representing an attractive catalyst for large-scale water-splitting technologies.

Efficient hierarchically synthesized Fe2P nanoparticles embedded in an N,P-doped mesoporous carbon catalyst for the oxygen reduction reaction

Novel Fe2P nanoparticles encapsulated in an N,P-doped three-dimensional porous carbon catalyst were synthesized and displayed excellent ORR performance.

Porous superstructures constructed from ultrafine FeP nanoparticles for highly active and exceptionally stable hydrogen evolution reaction

We report the fabrication of porous FeP microsphere superstructures (SS) made up of ultrafine FeP NPs through a self-templated gas–solid phosphorization reaction. The FeP SS exhibit highly active and exceptionally stable HER performance at small electrocatalyst loading mass.

Carbon-coated FeP nanoparticles anchored on carbon nanotube networks as an anode for long-life sodium-ion storage.

A novel electrode design strategy of carbon-coated FeP particles anchored on a conducting carbon nanotube network (CNT@FeP-C) is designed to achieve superior sodium ion storage. Such a unique structure demonstrated excellent long-life cycling stability (a 95% capacity retention for more than 1200 cycles at 3 A g-1) and rate capability (delivered 272 mA h g-1 at 8 A g-1).

Fe2P nanoparticles as highly efficient freestanding co-catalyst for photocatalytic hydrogen evolution

Design of non-noble-metal artificial photosynthesis system that can split water with high apparent quantum yield (AQY) and robust stability remains a fundamental challenge. Here we report that a physical mixture of Fe2P nanopaticles (NPs) and CdS nanosheets (NSs) can gives AQY of photocatalytic hydrogen production as high as 90% at 420 nm monochromatic light with ethanol as electron donor at strong alkaline conditions. The highest rate for hydrogen production reached about 220 mmol g−1 h−1. In this hybrid photocatalyst system, free standing Fe2P NPs act as efficient and robust noble-metal-free co-catalysts and ultrathin CdS NSs are used as the photosensitizer. PL and TRPL results demonstrate that photoexcited electron can transfer from the conduction band of the excited CdS to Fe2P, which aided charge separation and enhanced the hydrogen evolution activity. Femtosecond transient absorption result reveals that the time-averaged interfacial electron transfer (ET) rate constant (<kET>) from CdS NSs to Fe2P is about 7.4 × 109 s−1 under the guarantee of the scavenging of photoexcited hole immediately, which is one order faster than the electron relaxation rate in pure CdS NSs.

Covalent Porphyrin Framework-Derived Fe2P@Fe4N-Coupled Nanoparticles Embedded in N-Doped Carbons as Efficient Trifunctional Electrocatalysts.

A new porous covalent porphyrin framework (CPF) filled with triphenylphosphine was designed and synthesized using the rigid tetrakis(p-bromophenyl)porphyrin (TBPP) and 1,3,5-benzenetriboronic acid trivalent alcohol ester as building blocks. The carbonization of this special CPF has afforded coupled Fe2P and Fe4N nanoparticles embedded in N-doped carbons (Fe2P/Fe4N@N-doped carbons). This CPF serves as an "all in one" precursor of Fe, N, P, and C. The porous property and solid skeleton of the CPF endow Fe2P/Fe4N@N-doped carbons with porous structure and a high degree of graphitization. As a result, Fe2P/Fe4N@N-doped carbons exhibited highly efficient multifunctional electrocatalytic performance for water splitting and oxygen electroreduction. Typically, Fe2P/Fe4N@C-800, obtained at a heat-treatment temperature of 800 °C, showed an ORR half-wave potential of 0.80 V in alkaline media and 0.68 V in acidic media, close to that of commercial Pt/C catalysts. Fe2P/Fe4N@C-800 also displayed efficient OER and HER activities, comparable to other phosphide and nitride electrocatalysts. The coupled Fe4N and Fe2P nanoparticles embedded in carbons exert unique catalytic efficiency for water splitting and fuel cells.

Large-Scale Synthesis of Carbon-Shell-Coated FeP Nanoparticles for Robust Hydrogen Evolution Reaction Electrocatalyst.

A highly active and stable non-Pt electrocatalyst for hydrogen production has been pursued for a long time as an inexpensive alternative to Pt-based catalysts. Herein, we report a simple and effective approach to prepare high-performance iron phosphide (FeP) nanoparticle electrocatalysts using iron oxide nanoparticles as a precursor. A single-step heating procedure of polydopamine-coated iron oxide nanoparticles leads to both carbonization of polydopamine coating to the carbon shell and phosphidation of iron oxide to FeP, simultaneously. Carbon-shell-coated FeP nanoparticles show a low overpotential of 71 mV at 10 mA cm-2, which is comparable to that of a commercial Pt catalyst, and remarkable long-term durability under acidic conditions for up to 10 000 cycles with negligible activity loss. The effect of carbon shell protection was investigated both theoretically and experimentally. A density functional theory reveals that deterioration of catalytic activity of FeP is caused by surface oxidation. Extended X-ray absorption fine structure analysis combined with electrochemical test shows that carbon shell coating prevents FeP nanoparticles from oxidation, making them highly stable under hydrogen evolution reaction operation conditions. Furthermore, we demonstrate that our synthetic method is suitable for mass production, which is highly desirable for large-scale hydrogen production.

Iron Phosphide Nanoparticles As an Efficient Electrocatalyst for the Oxygen Evolution Reaction in Alkaline Solution

Splitting water to hydrogen and oxygen through hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is basis to feed the fuel cell. OER is a thermodynamically uphill process as it requires higher potential to form O2 molecule. The best known catalysts to split water with low overpotential are the oxides of Ir and Ru. As these catalysts are precious metals there has been intensive research to substitute them with earth-abundant resources. The new catalyst should fulfill the following: (i) the catalyst to split water has to use minimal energy (measured as applied voltage and referred to as overpotential); (ii) should comprise of earth abundant elements; (iii) should be stable; (iv) should be scalable.1 Transition metal oxides have been recently identified as high-efficiency catalysts for oxygen and/or hydrogen evolution reaction. Apart from the oxides there has been reports of sulfide, selenide and nitride based catalysts.2 Although transition metal phosphides has recently gathered attention as HER catalysts,3 very less metal phosphides have been reported as OER electrocatalyst. In this presentation, ultra-small iron phosphide nanoparticles as well nanoparticle composite with reduced graphene oxide (FeP-rGO) has been reported as efficient electrocatalysts for OER under alkaline conditions. FeP nanoparticles require an overpotential of 290 mV @ 10 mAcm-2. It is well known that rGO is a good conductor and a support material for the catalysts. Hence, mixing of FeP nanoparticles with rGO has improved the catalytic efficiency further by reducing the overpotential to 260 mV to achieve 10 mAcm-2 current density4. The FeP nanoparticles and FeP-rGO composite showed the lowest overpotential at 10 mA/cm2 that has observed among the pnictide making these the most-efficient phosphide based OER catalyst till date. The hybrid catalyst showed a low Tafel slope of 50.8 mV/dec. The stability of the catalyst was excellent with 4h of continuous oxygen evolution and the catalytic activity was retained with a similar overpotential @ 10 mAcm-2. The synthesis of hybrid catalysts, detailed characterization, and electrochemical studies including liner scan voltammetry (LSV), choronoamperometry will be discussed in detail.

Phytic acid-derivative transition metal phosphides encapsulated in N,P-codoped carbon: an efficient and durable hydrogen evolution electrocatalyst in a wide pH range.

Applications of highly-efficient and durable non-precious metal electrocatalysts for hydrogen evolution reaction (HER) have great potential to relieve the energy crisis. Here, we demonstrate a green method for fabrication of a number of transition metal phosphides (TMPs) by pyrolyzing melamine and self-assembled phytic acid (PA) cross-linked metal complexes. The obtained materials consisting of TMP nanoparticles (NPs) are encapsulated in N,P-codoped carbon (NPC). Among TMPs, the resultant FeP NPs encapsulated in the NPC matrix (FeP NPs@NPC) show the highest HER activity at all pH values. At a current density of 10 mA cm-2, FeP NPs@NPC displays overpotentials of 130, 386 and 214 mV in 0.5 M H2SO4, 1.0 M phosphate buffer solution (PBS) and 1.0 M KOH, respectively. Additionally, the encapsulation by NPC effectively prevents FeP NPs from corrosion, exhibiting almost unfading catalytic activity after 10 h testing in acidic, neutral and basic electrolytes. More importantly, other TMPs wrapped in NPC (CoP NPs@NPC and Ni2P NPs@NPC) can be easily obtained by this method, which also exhibit relatively high activity toward HER. Therefore, this generic synthesis strategy opens a door for unprecedented design and fabrication of novel low-cost TMP based electrocatalysts for HER and other electrochemical applications.

Iron phosphide nanocrystals decorated in situ on heteroatom-doped mesoporous carbon nanosheets used for an efficient oxygen reduction reaction in both alkaline and acidic media

Oxygen reduction catalysts based on heteroatom-doped mesoporous carbon nanosheets loaded with highly crystalline FeP nanoparticles (FeP@FePNCs) were fabricated using a simple, one-step carbonization–phosphization methodology.

Electrochemical Activity of Iron Phosphide Nanoparticles in Hydrogen Evolution Reaction

Iron phosphide (FeP) has been recently demonstrated as a very attractive electrocatalyst for the hydrogen evolution reaction (HER). However, the understanding of its properties is far from satisfactory. Herein, we report the HER performance of FeP nanoparticles is enhanced after a stability test due to reduced surface-charge-transfer resistance in the HER process. The synthetic temperature and reactant ratio are important for surface-charge-transfer resistance, the electrochemically active surface area, and HER activity. Hydrogenation apparently improves the HER performance of FeP nanoparticles by reducing the surface-charge-transfer resistance, overpotential, and Tafel slope. Enhanced HER performance is observed after a stability test for both bare and hydrogenated FeP nanoparticles in the HER due to reduced surface-charge-transfer resistance. Thus, this study may enrich our knowledge and understanding to advance HER catalysis for electrochemical hydrogen generation.

Robustly photogenerating H2 in water using FeP/CdS catalyst under solar irradiation.

Photosplitting water for H2 production is a promising, sustainable approach for solar-to-chemical energy conversion. However, developing low-cost, high efficient and stable photocatalysts remains the major challenge. Here we report a composite photocatalyst consisting of FeP nanoparticles and CdS nanocrystals (FeP/CdS) for photogenerating H2 in aqueous lactic acid solution under visible light irradiation. Experimental results demonstrate that the photocatalyst is highly active with a H2-evolution rate of 202000 μmol h−1 g−1 for the first 5 h (106000 μmol h−1 g−1 under natural solar irradiation), which is the best H2 evolution activity, even 3-fold higher than the control in situ photo-deposited Pt/CdS system, and the corresponding to an apparent quantum efficiency of over 35% at 520 nm. More important, we found that the system exhibited excellent stability and remained effective after more than 100 h in optimal conditions under visible light irradiation. A wide-ranging analysis verified that FeP effectively separates the photoexcited charge from CdS and showed that the dual active sites in FeP enhance the activity of FeP/CdS photocatalysts.