NiCoP Nanoparticles Research Articles

In Situ Generation of NiCoP Nanoparticles on a Bimetal–Organic Framework for High-Performance Supercapacitors

The rational exploration of hybrid materials with well-defined compositions and structures/morphologies is essential for achieving high-performance electrodes for supercapacitors. Here, in situ dispersion and anchoring of NiCoP nanoparticles (NPs) on a bimetal-organic framework (Co1Ni2-MOF) by a controllable partial phosphorization approach are reported. The phosphating temperature and time significantly affect the specific capacitance of NiCoP/Co1Ni2-MOF-X-Y (where X and Y represent the phosphating temperature and time, respectively). Co1Ni2-MOF provides anchoring sites for confining NiCoP NPs, effectively improving the stability of NiCoP NPs. Highly dispersed NiCoP NPs facilitate OH- adsorption, boosting the redox reaction kinetics. NiCoP/Co1Ni2-MOF-350-2 with optimized phosphating conditions exhibits a high specific capacitance of 525 F g-1 at 0.5 A g-1, which is superior to that of the precursor of Co1Ni2-MOF. Moreover, a hybrid supercapacitor constructed with NiCoP/Co1Ni2-MOF-350-2 and activated carbon shows a high specific capacitance and outstanding long-term stability.

Nano-Modulated of Nicop Nanosheets Incorporating with Nicop Nanoparticles for Superior Water Splitting

Nano-Modulated of Nicop Nanosheets Incorporating with Nicop Nanoparticles for Superior Water Splitting

One-step synthesis of amorphous NiCoP nanoparticles by electrodeposition as highly efficient electrocatalyst for hydrogen evolution reaction in alkaline solution

Exploring a simple, low-cost preparation method to synthesize excellent catalyst for hydrogen evolution reaction (HER) in alkaline solution is highly meaningful for large-scale electrolysis of water for hydrogen production. Herein, a one-step electrodeposition method with simultaneous electrodeposition and phosphation was proposed to synthesize the three-dimensional NiCoP/carbon cloth (NiCoP/CC) nanoparticles at room temperature on the conductive carbon cloth (CC). The results showed that the NiCoP nanoparticles covered by nanowires had an amorphous structure. The NiCoP/CC electrode exhibited a good catalytic activity in 1.0 M KOH solution. It required only 74, 101, 149 mV overpotential for HER in basic solution to obtain current densities of − 10, − 20, − 50 mA cm−2, respectively, with a corresponding Tafel slope of 89.5 mV dec−1. Furthermore, after 24 h constant voltage test, the current density of NiCoP/CC only showed 2% decay, indicating a good stability. The obtained excellent catalytic activity can be attributed to the amorphous structure, the synergetic effect of Ni and Co, the charge transfer among Ni/Co and P, and nanoparticles in situ grown on carbon cloth. The simple one-step electrodeposition method shows a very promising potential for the preparation of bimetallic phosphides.

Facile one-step synthesis of Ru doped NiCoP nanoparticles as highly efficient electrocatalysts for oxygen evolution reaction.

Transition metal phosphides (TMPs) as ever-evolving electrocatalytic materials have attracted increasing attention in water splitting reactions owing to their cost-effective, highly active and stable catalytic properties. This work presents a facile synthetic route to NiCoP nanoparticles with Ru dopants which function as highly efficient electrocatalysts for oxygen evolution reaction (OER) in alkaline media. The Ru dopants induced a high content of Ni and Co vacancies in NiCoP nanoparticles, and the more defective Ru doped NiCoP phase than undoped NiCoP ones led to a greater number of catalytically active sites and improved electrical conductivity after undergoing electrochemical activation. The Ru doped NiCoP catalyst exhibited high OER catalytic performance in alkaline media with a low overpotential of 281 mV at 10 mA cm-2 and a Tafel slope of 42.7 mV dec-1 .

Promoting high-energy supercapacitor performance over NiCoP/N-doped carbon hybrid hollow nanocages via rational architectural and electronic modulation

Delicately engineering nano-architecture and electronic structure can assist in constructing the high-performance electrode materials for high-energy supercapacitor. Herein, a hollow nanocage is in-situ introduced into bimetallic phosphide-based materials via a green self-template strategy at room temperature. The homogeneous hollow configuration that N-doped carbon confined NiCoP nanoparticles hybrid nanocages (NiCoP/NC) is harvested via elaborately manipulating the physicochemical properties at the molecular level. This well-defined hollow geometry ensures the convenient electrolyte access for electroactive sites, thus facilitating the electrochemical activities. X-ray photoelectron spectroscopy reveals the electronic interaction among Ni, Co and P elements, which can induce an appropriate electric-field environment favors for the charge-carriers immigration. Density-functional-theory simulations indicate the increased electronic states of d-orbital around the Fermi level, which benefit for lower OH– adsorption energies (-3.80 eV), therefore resulting the faster electrochemical dynamics. Accordingly, as-prepared NiCoP/NC electrode achieves superb rate-capability (1127 and 873F g−1 at 1 and 16 A g−1, respectively) and long-term durability (75.5% retention after 8000 cycles). Furthermore, a hybrid supercapacitor based on NiCoP/NC cathode demonstrates an ultra-high energy density (52.5 Wh kg−1), outperforming similar hybrid devices. Our studies successfully give an insight into the relationship between nano-morphology, electronic modulation and electrochemical performance, which can provide some guidance for garnering a desirable electrode material.

NiCoP nanoparticles anchored on CdS nanorods for enhanced hydrogen production by visible light-driven formic acid dehydrogenation

Photocatalytic dehydrogenation of formic acid (FA), HCOOH→H2+CO2, is a promising strategy for hydrogen production. Although tremendous efforts have been made, developing efficient and robust system driven by visible light without noble metal still remains a huge challenge. Herein, we report for the first time the use of NiCoP nanoparticles anchored on CdS nanorods (NiCoP@CdS NRs) as a highly efficient and robust catalyst for photocatalytic FA dehydrogenation. NiCoP nanoparticles as cocatalyst can effectively separate the electron-hole pairs generated by CdS NRs. The H2 production rate of the NiCoP@CdS nanorods reached ~354 μmol mg−1 h−1 under visible light irradiation (λ > 420 nm) and the apparent quantum yield (AQY) was ~45.5 % at 420 nm which are among the best values ever reported in photocatalytic FA dehydrogenation systems. This work provides a prospective strategy for developing noble-metal-free photocatalytic FA dehydrogenation systems and hydrogen-based energy applications.

Controlled Synthesis of NiCoP/g‐C3N4 Heterostructured Hybrids for Enhanced Visible‐Light‐Driven Hydrogen Evolution

AbstractAn innovative system of graphitic C3N4 with NiCoP as two‐component heterostructured hybrids (NiCoP/g‐C3N4) with efficiently photocatalytic performances for hydrogen production is demonstrated and a simple, morphologically controlled catalyst with an extremely low phosphide load was developed. The hydrogengenerate rate is 1067.11 μmol g−1 h−1 using 1 ωt% NiCoP/g‐C3N4. The incorporation of monodisperse NiCoP nanoparticles into g‐C3N4 effectively optimizes the electronic structures of the hybrids, enhances the corresponding interaction and the activity of hydrogen catalytic site, Moreover,NiCoP/g‐C3N4 Heterostructured Hybrids displayed the favorable stability during the photocatalytic.

Enhanced Photoelectrochemical Performance of Hematite Photoanode by Decorating NiCoP Nanoparticles Through a Facile Spin Coating Method

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.

NiCoP nanoparticles encapsulated in cross-linked graphene aerogel to efficient hydrogen evolution reaction

The structure of a cheap and high-efficient electrochemical catalyst for hydrogen evolution reaction (HER) plays an essential impact in producing updatable hydrogen energy. Herein, we introduce a facile way to synthesize graphene aerogel inlaid with NiCoP nanoparticles (NiCoP-NPs@GA), which used seaweed biomass as precursors through a phosphorization route. In this work, graphene oxide (GO) with thin layer structure and carbon aerogel (CA) skeleton with a three-dimensional (3D) structure were connected in series to form a 3D-graphene aerogel (GA) as a composite material for conductive matrix. In addition, NiCoP nanoparticles (NiCoP-NPs) are uniformly encapsulated in GA nanoflakes, and the particles size can be controlled by the nanopores of the GA nanoflakes. The excellent 3D-GA matrix contains numerous open pores which can effectively circumvent volume expansion and aggregation of the NiCoP-NPs. Compared with NiCoP bulk, the NiCoP-NPs@GA demonstrated the advantages of larger specific surface areas and better HER overpotential function of only 109 m V with an operational density of 10 mA/cm2, along with a less Tafel gradient of 63 mV/dec in 0.5 M H2SO4. Our protocol opens a new avenue for synthesis of many transition metal catalytic makings and provides a preliminary research for their potential function in industry.

Porous NiCoP@P–C hybrid as efficient positive electrodes for high-performance supercapacitors

Abstract Electrode materials with excellent capacitance performance remain on urgent need for energy storage devices. In this study, we successfully fabricated porous P-doped carbon-supported NiCoP nanoparticles (NiCoP@P–C) by chelating sodium alginate with Ni2+ and Co2+ ions and subsequently performing a high-temperature calcination process. The carbonization process involved phosphating the metal ions to form bimetallic NiCoP nanoparticles and doping the P element into the carbon framework. The as-prepared material integrated the merits of metal phosphide (high theoretical specific capacitance), bimetal (excellent electrochemical conductivity), and porous structure (rapid ion transportation). The sample consequently exhibited outstanding electrochemical properties with an ultrahigh specific capacitance of 920 F g−1 (0.5 A g−1) and a high cycle stability of 84% over 5000 cycles with a small mass loading of 3.6 mg cm−2. Moreover, an asymmetric supercapacitor assembled with NiCoP@P–C-500 as the positive electrode and activated carbon as the negative electrode delivered a maximum energy density of 57.8 W h kg−1 at a power density of 522 W kg−1.

A facile strategy to prepare NiCoP nanoparticles wrapped in nitrogen doped porous carbon spheres for high-performance lithium-ion battery

In this work, we propose a facile and one-step strategy to synthesize NiCoP nanoparticles (NPs) embedded in nitrogen doped porous carbon spheres (NiCoP@N-PCS) by direct carbonating a bimetal-organophosphine framework. In application to Lithium ions battery, the NiCoP NPs enables to promote the redox reaction while the N-PCS acts as buffer layer to alleviate the volume changes in the charge/discharge process. On the other hand, the novel nanostructure provides abundant tunnels for Li+ diffusion. As a result, the NiCoP@N-PCS exhibits a highly reversible specific capacity of ～588.3 mAh∙g−1 after 100 cycles at 0.1 A·g−1 and excellent rate performance (280 mAh∙g−1 at 2.0 A·g−1).

5 nm NiCoP nanoparticles coupled with g-C3N4 as high-performance photocatalyst for hydrogen evolution

Graphitic carbon nitride (g-C3N4) coupled with NiCoP nanoparticles with sizes around 5 nm have been fabricated via a controllable alcohothermal process. NiCoP is an excellent electron conductor and cocatalyst in photocatalytic reactions. The coupling between tiny NiCoP nanoparticles and g-C3N4 through in-situ fabrication strategy could be a promising way to eliminate the light screening effect, hinder the recombination of photo-induced charge carriers, and improve the charge transfer. The NiCoP/g-C3N4 nanohybrids exhibit an excellent photocatalytic activity in the hydrogen generation, with a significantly improved performance compared with original g-C3N4, CoP/g-C3N4 and Ni2P/g-C3N4, respectively. This study paves a new way to design transition metal phosphides-based photocatalysts for hydrogen production.

Calcination/phosphorization of dual Ni/Co-MOF into NiCoP/C nanohybrid with enhanced electrochemical property for high energy density asymmetric supercapacitor

Binary metal compounds have higher conductivity and richer redox reactions due to the co-existence and synergism of different transition metals. Besides, carbon in composite materials has the advantage of enhancing electronic conductivity to promote fast electron transmission. Herein, a series of NimPn/C, Ni2P/C, Co2P/C and NixCo2-xP/C nanohybrids with different Ni/Co molar ratios were synthesized by in-situ calcination/phosphorization of MOF precursors. These nanohybrid materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive spectrometer and electrochemical tests. The NiCoP/C material possesses a granular structure with NiCoP nanoparticles anchored in a large number of carbon. Taking advantage of the bimetallic synergism and carbon anchoring effect, the as-prepared NiCoP/C sample delivers the most prominent specific capacities of 775.7C g−1 at 1 A g−1, and 582.4C g−1 at 20 A g−1 (20-fold) with a superior rate capability of 75.1% retention, much superior to those of the corresponding NimPn/C, Ni2P/C, Co2P/C, other NixCo2-xP/C samples and various reported metal phosphide nanostructures/nanocomposites. Furthermore, the constructed NiCoP/C//activated carbon asymmetric supercapacitor can exhibit a high energy density of 47.6 Wh kg−1 at a power density of 798.9 W kg−1, which was superior to those previously reported of Ni/Co phosphide nanomaterials.

Microwave absorption enhancement of nickel cobalt phosphides by decorating on reduced graphene oxide

Herein, NiCoP nanoparticles decorated on reduced graphene oxide (rGO) were synthesized through a two-step hydrothermal-phosphorization route as enhanced microwave absorbers. Microstructure investigations indicate that NiCoP nanoparticles are uniformly anchored on the surface of rGO. Compared with the bare NiCoP, NiCoP/rGO nanocomposites reveal clearly improved microwave absorbing performance. The strongest reflection loss (RL) values of NiCoP/rGO hybrid absorber can reach −20.61 dB at 6.43 GHz with a matching thickness of 4.4 mm, and a broad effective absorption bandwidth (RL < −10 dB) of 4.13 GHz (13.87–18 GHz) can be obtained at only 2.0 mm, while the RL values of the pure NiCoP cannot reach −10 dB in the entire measurement frequency range. This improvement of microwave absorption is ascribed to the polarization, interface interaction and synergistic effect between NiCoP and rGO nanosheets. NiCoP/rGO nanocomposites are expected to be novel microwave absorption materials with high microwave absorption properties.

In Situ Synthesis of NiCoP Nanoparticles Supported on Reduced Graphene Oxide for the Catalytic Hydrolysis of Ammonia Borane.

Developing highly efficient and stable noble-metal-free catalysts toward catalytic hydrolysis of ammonia borane (AB) for hydrogen storage is highly desirable, but still remains challenging. We report a simple and in situ co-reduction approach to synthesize bimetallic NiCoP nanoparticles (NPs) supported on reduced graphene oxide (rGO). Thanks to the strong electronic interaction between Ni, Co, and P, the as-synthesized Co89.8 Ni10.2 P11.7 /rGO catalyst exhibits superior catalytic performance towards hydrolysis of AB, with the turnover frequency value (TOF) of 18.6 min-1 , which is about 2.5 times higher than that of NiCo/rGO.

Bimetallic NiCoP nanoparticles incorporating with carbon nanotubes as efficient and durable electrode materials for dye sensitized solar cells

In this research, the bimetallic NiCoP nanoparticles and NiCoP/carbon nanotubes (CNTs) composites were successfully synthesized, and their performances as counter electrodes (CEs) for dye sensitized solar cells were investigated. The optimal composite CE (NiCoP-CNTs-3) exhibits outstanding photoelectric conversion efficiency (PCE) of 7.24%, which exceeds the single NiCoP (4.71%) or CNTs electrode (6.05%) and is on par with the standard Pt CE (7.12%) under same conditions. The electrochemical properties of NiCoP-CNTs electrodes were also characterized by utilizing the electrochemical impedance spectroscopy (EIS), Tafel polarization curves and cyclic-voltammetry (CV). The results indicate that NiCoP-CNTs-3 electrode holds Pt-like good electrocatalytic activity towards reduction of I3−. In addtion, the composite CE shows a reliably electrochemical stability. The present materials in this study may pave a way for the practical applications of Pt-free DSSCs.

Boron nitride supported NiCoP nanoparticles as noble metal-free catalyst for highly efficient hydrogen generation from ammonia borane

Herein, ternary metal phosphides NiCoP nanoparticles supported on porous hexagonal boron nitride (h-BN) was fabricated via hydrothermal-phosphorization strategy. The as-prepared Ni0.8Co1.2P@h-BN exhibited excellent catalytic performance for the hydrogen generation from ammonia borane (AB) hydrolysis, with an initial turnover frequency of 86.5 mol(H2) mol(Ni0.8Co1.2P) −1 min−1 at 298 K. The experimental outcome can be attributed to the synergistic effect between Ni, Co and P, as well as the strong metal-support interaction between NiCoP and h-BN. This study presents a new paradigm for supporting transition metal phosphides, and provides a new avenue to develop high performance and low cost non noble metal catalysts for hydrolysis of AB.

Electrospun Carbon Nanofibers Encapsulated with NiCoP: A Multifunctional Electrode for Supercapattery and Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution Reactions

AbstractFunctionalizing nanostructured carbon nanofibers (CNFs) with bimetallic phosphides enables the material to become an active electrode for multifunctional applications. A facile electrospinning technique is utilized for the first time to develop NiCoP nanoparticles encapsulated CNFs that are used as an energy storage system of supercapattery, and as an electrocatalyst for oxygen reduction, oxygen evolution, and hydrogen evolution reaction in KOH electrolyte. Evolving from the inclusion of bimetallic phosphide nanoparticles, the NiCoP/CNF electrode unveils superior‐specific capacitance (333 Fg−1 at 2 Ag−1) and rate capability (87%). The fabricated supercapattery device offers a voltage of 1.6 V that supplies a remarkable energy density (36 Wh kg−1) along with an improved power density (4000 W kg−1) and unwavering cyclic stability (25 000 cycles). Meanwhile, the NiCoP/CNF electrode has simultaneously performed well as a multifunctional electrocatalyst for oxygen reduction reaction at a half‐wave potential of 0.82 V versus reversible hydrogen electrode and can attain a current density of 10 mA cm−2 at a very low overpotential of 268 and 130 mV for the oxygen evolution reaction and hydrogen evolution reaction, respectively. Thus, the NiCoP/CNF with all its inimitable electrode properties has profoundly proved its proficiency at handling multifunctional challenges in terms of both storage and conversion.

Highly dispersed NiCoP nanoparticles on carbon nanotubes modified nickel foam for efficient electrocatalytic hydrogen production

Advanced materials for electrocatalytic hydrogen evolution reaction (HER) are significant for future sustainable energy. On the basis of transition metal phosphides (TMPs), we developed a method to engineer well-dispersed NiCoP nanoparticles by introducing carbon nanotubes on Ni Foam (CNT/NF) as a high active electrocatalyst for HER. The obtained catalysts were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS) and energy-dispersive X-ray spectroscopy (EDS), and the catalytic activity was evaluated by electrochemical technique. The as-prepared NiCoP/CNT/NF electrode exhibits efficient electrocatalytic activity towards HER with an onset overpotential of 69mV and a small Tafel slope in 1M KOH. These results suggest the possibility for creating binder-free CNTs supported and element doped electrode in electrochemical water splitting.

Ternary NiCoP nanoparticles assembled on graphene for high-performance lithium-ion batteries and supercapacitors

We demonstrate that ternary NiCoP nanoparticles can be self-assembled on graphene at room temperature by a solution-phase method and our electrode materials exhibit a high performance for LIBs and supercapacitors.