Search Results (35)

Chlorpheniramine maleate (CPM) is a first-generation antihistamine that is frequently used to treat allergic reactions. However, excessive consumption presents potential health risks. Therefore, it is crucial to develop a quick and precise technique for identifying CPM levels. In this study, nickel cobalt phosphide (NiCoP), a binary metal phosphide, was successfully incorporated into carbon nanofibers. This involved creating a pore structure by adding polyvinylpyrrolidone (PVP) as a pore-forming template to a polyacrylonitrile (PAN) substrate via electrostatic spinning. An innovative electrochemiluminescent sensor for CPM detection was constructed using NiCoP/PVP/PAN carbon nanofibers (NiCoP/PVP/PAN/CNFs). Under optimal conditions, the electrochemical behavior of CPM was studied using NiCoP/PVP/PAN/CNF-modified working electrodes. These findings demonstrate that the three-dimensional porous network architecture of NiCoP/PVP/PAN/CNFs enhances the conductive properties of the material. Consequently, an electrochemical optical sensor fabricated using this structure exhibited remarkable performance. The linear detection range of the sensor was 1 × 10⁻⁸–7 × 10⁻⁵ mol/L, and the detection limit was 7.8 × 10⁻¹⁰ mol/L. When human urine and serum samples were examined, the sensor was found to have a high recovery rate (94.35–103.36%), which is promising for practical applications. Full article

Hydrogen energy holds great promise for alleviating energy and environmental issues, with alkaline electrochemical water splitting being a key approach for hydrogen production. However, the high cost and limited availability of noble-metal catalysts hinder its widespread application. This study presents a novel method to fabricate a NiFeP-CoP/CF electrode. By growing CoOOH nanosheets on Co foam at low temperatures and filling the gaps between nanosheets with Ni and Fe phosphides, the prepared electrode exhibits outstanding electrocatalytic performance. For the oxygen evolution reaction (OER) in alkaline media, it requires overpotentials of only 235 mV and 290 mV to reach current densities of 10 mA cm⁻² and 100 mA cm⁻², respectively. In the case of the hydrogen evolution reaction (HER), overpotentials of 89 mV and 172 mV are needed to achieve current densities of −10 mA cm⁻² and −100 mA cm⁻². The NiFeP-CoP/CF-based electrolytic cell requires a cell voltage of only 1.70 V to achieve a current density of 100 mA cm⁻² for overall water splitting. Moreover, during long-term continuous operation at 100 mA cm⁻², the overpotential for OER remains constant while that for HER decreases. The low-temperature growth of CoOOH nanosheets on Co foam provides a new strategy for large-scale electrode production applicable in electrochemical processes and pollutant degradation. Significantly, filling the nanosheet gaps with phosphides effectively enhances the electrocatalytic performance of the system. This work offers a facile and cost-effective technique for the large-scale production of metallic (oxyhydr)hydroxides for electrocatalytic water splitting, showing great potential for industrial applications. Full article

To meet the growing demand for renewable energy, developing efficient and cost-effective photocatalytic materials is crucial. Specifically, designing photocatalysts with high charge separation efficiency and abundant hydrogen production active sites remains a key challenge for practical applications. In this study, a carbon nitride (g-C₃N₄)-based ternary photocatalyst has been constructed for enhanced photocatalytic H₂ production without the need for precious metal cocatalysts. CoO nanoparticles were loaded onto the surface of g-C₃N₄ via in situ thermal decomposition. Subsequently, a series of g-C₃N₄/CoO/CoP ternary composites were successfully prepared using a direct one-step phosphorization method. Under optimized conditions, the g-C₃N₄/CoO/CoP catalyst exhibits a hydrogen evolution activity of 1277.9 μmol·g⁻¹·h⁻¹, which is 4 times higher than that of g-C₃N₄/CoO (with g-C₃N₄ alone showing no hydrogen evolution activity). Its performance is comparable to that of the commonly used Pt cocatalyst. The performance improvement may be attributed to the tight bonding of N-P bonds, which effectively promotes the transport of photogenerated carriers, while the increased loading of CoP provides more active sites. The results offer a promising strategy for designing efficient and low-cost photocatalytic materials. Full article

High-performance and cost-efficient electrocatalysts and electrodes are needed to improve the hydrogen evolution reaction (HER) for the hydrogen (H₂) generation in electrolysers, including microbial electrolysis cells (MECs). In this study, free-standing carbon nanofiber (CNF) films with supported cobalt phosphide nanoparticles have been prepared by means of an up-scalable electrospinning process followed by a thermal treatment under controlled conditions. The produced cobalt phosphide-supported CNF films show to be nanoporous (pore volume up to 0.33 cm³ g⁻¹) with a high surface area (up to 502 m² g⁻¹) and with a suitable catalyst mass loading (up to 0.49 mg cm⁻²). Values of overpotential less than 140 mV at 10 mA cm⁻² have been reached for the HER in alkaline media (1 M KOH), which demonstrates a high activity. The high electrical conductivity together with the mechanical stability of the free-standing CNF films allowed their direct use as cathodes in a MEC reactor, resulting in an exceptionally low voltage operation (0.75 V) with a current density demand of 5.4 A m⁻². This enabled the production of H₂ with an energy consumption below 30 kWh kg⁻¹ H₂, which is highly efficient. Full article

Defect engineering, by adjusting the surface charge and active sites of CoP catalysts, significantly enhances the efficiency of the oxygen evolution reaction (OER). We have developed a new Co_1−xP_v catalyst that has both cobalt defects and phosphorus vacancies, demonstrating excellent OER performance. Under both basic and acidic media, the catalyst incurs a modest overvoltage, with 238 mV and 249 mV needed, respectively, to attain a current density of 10 mA cm⁻². In the practical test of alkaline electrocatalytic water splitting (EWS), the Co_1−xP_v || Pt/C EWS shows a low cell voltage of 1.51 V and superior performance compared to the noble metal-based EWS (RuO₂ || Pt/C, 1.66 V). This catalyst’s exceptional catalytic efficiency and longevity are mainly attributed to its tunable electronic structure. The presence of cobalt defects facilitates the transformation of Co²⁺ to Co³⁺, while phosphorus vacancies enhance the interaction with oxygen species (*OH, *O, *OOH), working in concert to improve the OER efficiency. This strategy offers a new approach to designing transition metal phosphide catalysts with coexisting metal defects and phosphorus vacancies, which is crucial for improving energy conversion efficiency and catalyst performance. Full article

The recent advancements of ionic liquids (ILs) and deep eutectic solvents (DESs) in the synthesis of cobalt-based catalysts for water splitting is reviewed. ILs and DESs possess unique physical and chemical properties, serving as solvents, templates, and reagents. Combined with calcination techniques, their advantages can be fully leveraged, enhancing the stability and activity of resulted catalysts. In these solvents, not only are they suitable for simple one-step calcination, but also applicable to more complex multi-step calcination, suitable for more complex reaction conditions. The designability of ILs and DESs allows them to participate in the reaction as reactants, providing metal and heteroatoms, simplifying the preparation system of cobalt phosphide, sulfide, and nitride. This work offers insights into design principles for electrocatalysts and practical guidance for the development of efficient and high-performance materials for hydrogen production and energy storage systems. Full article

Transition metal phosphides (TMPs) have been widely studied for water decomposition for their monocatalytic property for anodic or cathodic reactions. However, their bifunctional catalytic activity still remains a major challenge. Herein, hexagonal nickel-cobalt bimetallic phosphide nanoneedles with 1–3 μm length and 15–30 nm diameter supported on NF (Ni_xCo_2−xP NDs/NF) with adjusted electron structure have been successfully prepared. The overall alkaline water electrolyzer composed of the optimal anode (Ni_0.67Co_1.33P NDs/NF) and cathode (Ni_1.01Co_0.99P NDs/NF) provide 100 mA cm⁻² at 1.62 V. Gibbs Free Energy for reaction paths proves that the active site in the hydrogen evolution reaction (HER) is Ni and the oxygen evolution reaction (OER) is Co in Ni_xCo_2−xP, respectively. In the HER process, Co-doping can result in an apparent accumulation of charge around Ni active sites in favor of promoting HER activity of Ni sites, and ΔG_H* of 0.19 eV is achieved. In the OER process, the abundant electron transfer around Co-active sites results in the excellent ability to adsorb and desorb *O and *OOH intermediates and an effectively reduced ∆G_RDS of 0.37 eV. This research explains the regulation of electronic structure change on the active sites of bimetallic materials and provides an effective way to design a stable and effective electrocatalytic decomposition of alkaline water. Full article

In this study, the successful synthesis of bimetallic nickel/cobalt phosphide nanosheets (Ni-Co-P NSs) via the hydrothermal method and the subsequent high-temperature phosphorization process were both confirmed. Ni-Co-P NSs exhibited excellent electrocatalytic activity for the electrochemical non-enzymatic DA sensing. The surface morphologies and physicochemical properties of Ni-Co-P NSs were characterized by atomic force microscopy (AFM), field-emission scanning (FESEM), field-emission transmission electron microscopy (FETEM), and X-ray diffraction (XRD). Further, the electrochemical performance was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The metallic nature of phosphide and the synergistic effect of Ni/Co atoms in Ni-Co-P NSs provided abundant catalytic active sites for the electrochemical redox reaction of DA, which exhibited a remarkable consequence with a wide linear range from 0.3~50 μM, a high sensitivity of 2.033 µA µM⁻¹ cm⁻², a low limit of detection of 0.016 µM, and anti-interference ability. As a result, the proposed Ni-Co-P NSs can be considered an ideal electrode material for the electrochemical non-enzymatic DA sensing. Full article

The design of a reasonable heterostructure electrode to achieve enhanced areal performance for supercapacitors remains a great challenge. Here, we constructed hierarchical porous NiCoP/NiO nanocomposites anchored on Ni foam with tunable electronic and structural properties, as well as robust interfacial interaction. In NiCoP/NiO, the interconnected NiO nanosheets serve as a carrier with enriched anchoring sites to confine the NiCoP and improve its stability. Meanwhile, the ultrathin NiCoP nanosheets with bimetallic centers are connected with porous NiO nanosheets to form a reliable heterojunction, enhancing the electrochemical reaction kinetics. Taking advantage of the synergistic contribution of bimetallic centers, phosphides and unique structure, the NiCoP/NiO delivers a high areal specific capacitance (1860 mF cm⁻² at 5 mA cm⁻²), good rate performance of 78.5% at six times the increased current density, and remarkable durability (11.0% decrease after 10,000 cycles). Furthermore, the assembled hybrid supercapacitor NiCoP/NiO//porous-activated carbon (PAC) delivers a high areal energy density of 173.7 μWh cm⁻² (116.4 μWh cm⁻²) at 1.6 mW cm⁻² (32 mW cm⁻²). The results indicate that the design of the heterostructure interface with strong chemical interface and tunable electronic structure is an effective and promising approach to boost the electrochemical performance for advanced supercapacitors. Full article

The understanding of amorphous and heterojunction materials has been widely used in the field of electromagnetic wave absorption due to their unique physical and chemical properties. However, the effectiveness of individual strategies currently used is still limited. Well-designed compositions and amorphous structures simplify the effect of different polarization mechanisms on the absorption of electromagnetic waves. In this work, through the carbonization and controlled phosphating of one-dimensional Co Metal–Organic Framework (Co-MOF) nanorods, the synthesis of complex components and amorphous CoP_x with phosphorus vacancies is successfully accomplished, thus adjusting the optimization of electromagnetic parameters. Phosphorus-vacancy-induced defective polarization loss and enhanced-electronegativity-differences-induced dipole polarization loss synergistically as a dual-polarization strategy significantly improved the electromagnetic parameters and impedance matching. In conclusion, the electromagnetic parameters of the Co@CoP_x@C composites are indeed significantly regulated, with reflection losses of −55 dB and a bandwidth of up to 5.5 GHz. These innovative research ideas provide instructive thinking for the development of amorphous absorbers with vacancies. Full article

Supercapacitors (SCs) are widely used in energy storage devices due to their superior power density and long cycle lifetime. However, the limited energy densities of SCs hinder their industrial application to a great extent. In this study, we present a new combination of metallic phosphide–carbon composites, synthesized by directly carbonizing (Ni_1−xCo_x)₅TiO₇ nanowires via thermal chemical vapor deposition (TCVD) technology. The new method uses one-dimensional (1D) (Ni_1−xCo_x)TiO₇ nanowires as precursors and supporters for the in situ growth of intertwined porous CNF microspheres. These 1D nanowires undergo microstructure transformation, resulting in the formation of CoNiP nanoparticles, which act as excellent interconnected catalytic nanoparticles for the growth of porous 3D CNF microspheres. Benefiting from the synergistic effect of a unique 1D/3D structure, the agglomeration of nanoparticles can effectively be prevented. The resulting CNF microspheres exhibit an interconnected conductive matrix and provide a large specific surface area with abundant ion/charge transport channels. Consequently, at a scanning rate of 10 mV s⁻¹, its specific capacitance in 1.0 M Na₂SO₄ + 0.05 M Fe(CN)₆^3−/4− aqueous solution is as high as 311.7 mF cm⁻². Furthermore, the CoNiP@CNFs composite film-based symmetrical SCs show an ultrahigh energy density of 20.08 Wh kg⁻¹ at a power density of 7.20 kW kg⁻¹, along with outstanding cycling stability, with 87.2% capacity retention after 10,000 cycles in soluble redox electrolytes. This work provides a new strategy for designing and applying high-performance binary transition metal phosphide/carbon composites for next-generation energy storage devices. Full article

The exploitation of electrocatalysts with high activity and durability for the hydrogen evolution reaction is significant but also challenging for future energy systems. Transition metal phosphides (TMPs) have attracted a lot of attention due to their effective activity for the hydrogen evolution reaction, but the complicated preparation of metal phosphides remains a bottleneck. In this study, a green fabrication method is designed and proposed to construct N, P co-doped graphene (NPG)-supported cobalt phosphide (Co₂P) nanoparticles by using DNA as both N and P sources. Thanks to the synergistic effect of NPG and Co₂P, the Co₂P/NPG shows effective activity with a small overpotential of 144 mV and a low Tafel slope of 72 mV dec⁻¹ for the hydrogen evolution reaction. This study describes a successful green synthesis strategy for the preparation of high-performance TMPs. Full article

The development of low-cost and high-performance bifunctional electrocatalysts for overall water splitting is still challenging. Herein, we employed a facile electrodeposition method to prepare bifunctional cobalt phosphide for overall water splitting. The needle-like cobalt phosphide (Co-P-1) nanoarray is uniformly distributed on nickel foam. Co-P-1 exhibits excellent electrocatalytic activity for hydrogen evolution reaction (HER, 85 mV at 10 mA/cm², 60 mV/dec) and oxygen evolution reaction (OER, 294 mV at 50 mA/cm², 60 mV/dec). The cell-voltage of 1.60 V is found to achieve the current density of 10 mA/cm² for overall water splitting in the two-electrode system, comparable to that of previously reported Pt/C/NF||RuO₂/NF. The excellent electrocatalytic performance can be attributed to the needle-like structure with more active sites, accelerated charge transfer and evolved bubbles’ release. This work can provide new approach to the development of a bifunctional electrocatalyst for overall water splitting. Full article

The search for new hydrogen evolution reaction (HER) electrocatalysts with lower cost and higher activity and stability than noble metal catalysts is essential. In this regard cobalt phosphide is considered one of the most promising nanomaterials. The present work proposes a simple and efficient method for the synthesis of a nanocomposite of graphene–phosphorene structures decorated with CoP nanoparticles 2–5 nm in size via the electrochemical exfoliation of black phosphorus carried out in the presence of nitrogen-doped few-layer graphene structures and followed by solvothermal synthesis in a Co²⁺-containing solution. The obtained CoP/EEBP/N-FLGS nanocomposite demonstrates high electrocatalytic activity and stability towards HER in an alkaline medium. The nanocomposite is characterized by an overpotential of 190 mV at a current density of 10 mA cm⁻² as well as a small Tafel slope (78 mV dec⁻¹). These characteristics make the CoP/EEBP/N-FLGS nanocomposite superior to most electrocatalysts based on cobalt phosphides. The results of this study could be in demand for the future design and improvement of HER electrocatalysts. Full article

The construction of multi-level heterostructure materials is an effective way to further the catalytic activity of catalysts. Here, we assembled self-supporting MoS₂@Co precursor nanoarrays on the support of nickel foam by coupling the hydrothermal method and electrostatic adsorption method, followed by a low-temperature phosphating strategy to obtain Mo₄P₃@CoP/NF electrode materials. The construction of the Mo₄P₃@CoP heterojunction can lead to electron transfer from the Mo₄P₃ phase to the CoP phase at the phase interface region, thereby optimizing the charge structure of the active sites. Not only that, the introduction of Mo₄P₃ will make water molecules preferentially adsorb on its surface, which will help to reduce the water molecule decomposition energy barrier of the Mo₄P₃@CoP heterojunction. Subsequently, H* overflowed to the surface of CoP to generate H₂ molecules, which finally showed a lower water molecule decomposition energy barrier and better intermediate adsorption energy. Based on this, the material shows excellent HER/OER dual-functional catalytic performance under alkaline conditions. It only needs 72 mV and 238 mV to reach 10 mA/cm² for HER and OER, respectively. Meanwhile, in a two-electrode system, only 1.54 V is needed to reach 10 mA/cm², which is even better than the commercial RuO₂/NF||Pt/C/NF electrode pair. In addition, the unique self-supporting structure design ensures unimpeded electron transmission between the loaded nanoarray and the conductive substrate. The loose porous surface design is not only conducive to the full exposure of more catalytic sites on the surface but also facilitates the smooth escape of gas after production so as to improve the utilization rate of active sites. This work has important guiding significance for the design and development of high-performance bifunctional electrolytic water catalysts. Full article