Electrocatalytic Epoxidation of Cyclooctene on Surface Modified Ni Foam Using Water as Oxygen Source.

Electrochemical epoxidation of olefins using water as an oxygen atom source is emerging as an alternative approach for an atom economic and sustainable method towards a highly selective synthesis of epoxides. We report an electrochemical procedure for epoxidation of cyclooctene using water as the sole oxygen atom source over a sodium dodecyl sulfonate (SDS) modified nickel hydroxide Ni(OH)2 catalyst directly grown on Ni foam. The SDS modification facilitates the mass transfer of cyclooctene towards the anode, thus achieving a 2.5-fold higher conversion with more than 90 % selectivity towards the corresponding epoxide compared with pure Ni(OH)2 catalyst.

Enhanced Electrochemical Performance in Supercapacitors through KCu-Cy Based Metal-Organic Framework Electrodes.

In the realm of electronics and electric energy storage, the convergence of organic and metallic materials has yielded promising outcomes. In this study, we introduce a novel metal-organic polymer synthesized from Cyamelurate and copper (KCu-Cy) and explore its application as an electrode for a supercapacitor. This material was pressed onto a stainless-steel grid as a thin film and synthesized on nickel foam. Comprehensive characterization was carried out to confirm the synthesis, ensure phase purity, and investigate atomic interactions. Single Crystal X-ray Diffraction (SCXRD) and Powder X-ray Diffraction (PXRD) analyses verified the synthesis and phase purity, shedding light on atomic arrangements. Fourier Transform Infrared Spectroscopy (FTIR) analyses provided insights into characteristic peaks within the material. Thermal Gravimetric Analysis (TGA) gauged stability and durability. Electrochemical performance was assessed through cyclic voltammetry. Notably, the nickel-supported electrodes, devoid of binders, exhibited exceptional specific capacity, reaching 1210.89 F/g at a scan rate of 5 mV/s, in contrast to 363.73 F/g for the pressed thin film on the stainless-steel grid, which incorporated a conductive agent and binder. Cu-Cy displayed impressive cyclization resistance, with a capacity retention of 90 % even after 11000 cycles. These findings underline the promise of Cu-Cy as a high-performance electrode material for supercapacitors, particularly in binder-free configurations, and suggest its potential in advanced energy storage applications.

Synergistic integration of Ni-metal organic framework/SnS2nanocomposite and nickel foam electrode for ultrasensitive and selective electrochemical detection of albumin in simulated human blood serum.

Albumin is a vital blood protein responsible for transporting metabolites and drugs throughout the body and serves as a potential biomarker for various medical conditions, including inflammatory, cardiovascular, and renal issues. This report details the fabrication of Ni-metal organic framework/SnS2nanocomposite modified nickel foam electrochemical sensor for highly sensitive and selective non enzymatic detection of albumin in simulated human blood serum samples. Ni-metal organic framework/SnS2nanocomposite was synthesized using solvothermal technique by combining Ni-metal-organic framework (MOF) with conductive SnS2leading to the formation of a highly porous material with reduced toxicity and excellent electrical conductivity. Detailed surface morphology and chemical bonding of the Ni-MOF/SnS2nanocomposite was studied using scanning electron microscopy, transmission electron microscopy, Fourier transform infra-red, and Raman analysis. The Ni-MOF/SnS2nanocomposite coated on Ni foam electrode demonstrated outstanding electrochemical performance, with a low limit of detection (0.44µM) and high sensitivity (1.3µA/pM/cm2) throughout a broad linear range (100 pM-10 mM). The remarkable sensor performance is achieved through the synthesis of a Ni-MOF/SnS2nanocomposite, enhancing electrocatalytic activity for efficient albumin redox reactions. The enhanced performance can be attributed due to the structural porosity of nickel foam and Ni-metal organic framework, which favours increased surface area for albumin interaction. The presence of SnS2shows stability in acidic and neutral solutions due to high surface to volume ratio which in turn improves sensitivity of the sensing material. The sensor exhibited commendable selectivity, maintaining its performance even when exposed to potential interfering substances like glucose, ascorbic acid, K+, Na+, uric acid, and urea. The sensor effectively demonstrates its accuracy in detecting albumin in real samples, showcasing substantial recovery percentages of 105.1%, 110.28%, and 91.16%.

Bismuth sulfide micro flowers decorated nickel foam as a promising electrochemical sensor for quantitative analysis of melamine in bottled milk samples.

Here, we demonstrate hydrothermally grown bismuth sulfide (Bi2S3) micro flowers decorated nickel foam (NF) for electrochemical detection of melamine in bottled milk samples. The orthorhombic phase of hydrothermally grown Bi2S3is confirmed by the detailed characterization of x-ray diffraction and its high surface area micro flowers-like morphology is investigated via field emission scanning electron microscope. Furthermore, the surface chemical oxidation state and binding energy of Bi2S3/NF micro flowers is analyzed by x-ray photoelectron spectroscopy studies. The sensor exhibits a wide linear range of detection from 10 ng l-1to 1 mg l-1and a superior sensitivity of 3.4 mA cm-2to melamine using differential pulse voltammetry technique, with a lower limit of detection (7.1 ng l-1). The as-fabricated sensor is highly selective against interfering species of p-phenylenediamine (PPDA), cyanuric acid (CA), aniline, ascorbic acid, glucose (Glu), and calcium ion (Ca2+). Real-time analysis done in milk by the standard addition method shows an excellent recovery percentage of Ì´ 98%. The sensor's electrochemical mechanism studies reveal that the high surface area bismuth sulfide micro flowers surface interacts strongly with melamine molecules through hydrogen bonding and van der Waals forces, resulting in a significant change in the sensor's electrical properties while 3D skeletal Nickel foam as a substrate provides stability, enhances its catalytic activity by providing a more number /of active sites and facilitates rapid electron transfer. The work presented here confirms Bi2S3/NF as a high-performance electrode that can be used for the detection of other biomolecules used in clinical diagnosis and biomedical research.

Peroxymonosulfate activation by iron-cobalt bimetallic phosphide modified nickel foam for efficient dye degradation.

Novel catalysts with multiple active sites and rapid separation are required to effectively activate peroxymonosulfate (PMS) for the removal of organic pollutants from water. Therefore, an integrated catalyst for PMS activation was developed by directly forming Co-Fe Prussian blue analogs on a three-dimensional porous nickel foam (NF), which were subsequently phosphorylated to obtain cobalt-iron bimetallic phosphide (FeCoP@NF). The FeCoP@NF/PMS system efficiently degraded dye wastewater within 20 min. The system exhibited excellent catalytic degradation over a broad pH range and at high dye concentrations due to the presence of unique asymmetrically charged Coa+ and Pb- dual active sites formed by cobalt phosphides within FeCoP@NF. These active sites significantly enhanced the catalytic activity of PMS. The activation mechanism of PMS involves phosphorylation that accelerates electron transfer from FeCoP@NF to PMS, to generate SO4·-, ·OH, O2·-, and 1O2 active species. Three-dimensional FeCoP@NF could be readily recycled and showed good stability for PMS activation. In this study, a highly efficient, stable, and readily recyclable integrated catalyst was developed. This catalyst system effectively resolves the separation and recovery issues associated with conventional powder catalysts and has a wide range of potential applications in wastewater treatment.

Electrocatalytic reduction of nitrate to ammonia by Pd/In modified Nickel foam electrode in aqueous solution.

Nitrate pollution in surface water and ground water has drawn wide attention, which has brought challenges to human health and natural ecology. Electroreduction of nitrate to NH3 in waste water was a way to turn waste into wealth, which has attracted interest of many researchers. Using Nickel foam as substrate, we prepared Pd/In bimetallic electrode (NF-Pd/In) according to a two-step electrodeposition method. There are many irregularly shaped particles in the size range of 10 nm-100 nm accumulated on the surface of prepared NF-Pd/In electrode, which could supply high specific area and more active sites for nitrate electroreduction. FESEM-EDS, XRD and XPS analysis confirmed the uniform distribution of Pd and In on the surface of prepared NF-Pd/In electrode, with a mass ratio of 4.5/1. Above 96% of 100 mg/L NO3--N was removed and 95% of NH3 selectivity was reached after 5 h of reaction under -1.6 V vs. Ag/AgCl sat. KCl when using 0.05 mol/L of Na2SO4 as electrolyte. High concentration of NaCl (0.05 mol/L) in the test solution dramatically decreased the NH3 selectivity because the produced NH3 could be further oxidized to N2 by the formed HClO from Cl-. EIS tests indicated that the prepared NF-Pd/In electrode showed much lower electrode resistance than NF due to the adsorptive property and electrocatalytic ability for nitrate removal. Density functional theory (DFT) calculations indicated that the presence of In could promote the conversion of NO3- to *NO3 during the process of nitrate electroreduction to NH3. Circulating tests demonstrated the stability of prepared NF-Pd/In electrode.

Application of TiO2 Supported on Nickel Foam for Limitation of NOx in the Air via Photocatalytic Processes.

TiO2 was loaded on the porous nickel foam from the suspended ethanol solution and used for the photocatalytic removal of NOx. Such prepared material was heat-treated at various temperatures (400-600 °C) to increase the adhesion of TiO2 with the support. Obtained TiO2/nickel foam samples were characterized by XRD, UV-Vis/DR, FTIR, XPS, AFM, SEM, and nitrogen adsorption at 77 K. Photocatalytic tests of NO abatement were performed in the rectangular shape quartz reactor, irradiated from the top by UV LED light with an intensity of 10 W/m2. For these studies, a laminar flow of NO in the air (1 ppm) was applied under a relative humidity of 50% and a temperature of 28 °C. Concentrations of both NO and NO2 were monitored by a chemiluminescence NO analyzer. The adsorption of nitrogen species on the TiO2 surface was determined by FTIR spectroscopy. Performed studies revealed that increased temperature of heat treatment improves adhesion of TiO2 to the nickel foam substrate, decreases surface porosity, and causes removal of hydroxyl and alcohol groups from the titania surface. The less hydroxylated surface of TiO2 is more vulnerable to the adsorption of NO2 species, whereas the presence of OH groups on TiO2 enhances the adsorption of nitrate ions. Adsorbed nitrate species upon UV irradiation and moisture undergo photolysis to NO2. As a consequence, NO2 is released into the atmosphere, and the efficiency of NOx removal is decreasing. Photocatalytic conversion of NO to NO2 was higher for the sample heated at 400 °C than for that at 600 °C, although coverage of nickel foam by TiO2 was lower for the former one. It is stated that the presence of titania defects (Ti3+) at low temperatures of its heating enhances the adsorption of hydroxyl groups and the formation of hydroxyl radicals, which take part in NO oxidation. Contrary to that, the presence of titania defects in TiO2 through the formation of ilmenite structure (NiTiO3) in TiO2/nickel foam heated at 600 °C inhibits its photocatalytic activity. No less, the sample obtained at 600 °C indicated the highest abatement of NOx due to the high and stable adsorption of NO2 species on its surface.

Nitrogen-Tungsten Oxide Nanostructures on Nickel Foam as High Efficient Electrocatalysts for Benzyl Alcohol Oxidation.

Electrocatalytic alcohol oxidation (EAO) is an attractive alternative to the sluggish oxygen evolution reaction in electrochemical hydrogen evolution cells. However, the development of high-performance bifunctional electrocatalysts is a major challenge. Herein, we developed a nitrogen-doped bimetallic oxide electrocatalyst (WO-N/NF) by a one-step hydrothermal method for the selective electrooxidation of benzyl alcohol to benzoic acid in alkaline electrolytes. The WO-N/NF electrode features block-shaped particles on a rough, inhomogeneous surface with cracks and lumpy nodules, increasing active sites and enhancing electrolyte diffusion. The electrode demonstrates exceptional activity, stability, and selectivity, achieving efficient benzoic acid production while reducing the electrolysis voltage. A low onset potential of 1.38 V (vs. RHE) is achieved to reach a current density of 100 mA cm-2 in 1.0 M KOH electrolyte with only 0.2 mmol of metal precursors, which is 396 mV lower than that of water oxidation. The analysis reveals a yield, conversion, and selectivity of 98.41%, 99.66%, and 99.74%, respectively, with a Faradaic efficiency of 98.77%. This work provides insight into the rational design of a highly active and selective catalyst for electrocatalytic alcohol oxidation.

A combination of microbial electrolysis cells and bioaugmentation can effectively treat synthetic wastewater containing polycyclic aromatic hydrocarbon.

The anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) is challenging due to its toxic effect on the microbes. Microbial electrolysis cells (MECs), with their excellent characteristics of anodic and cathodic biofilms, can be a viable way to enhance the biodegradation of PAHs. This work assessed different cathode materials (carbon brush and nickel foam) combined with bioaugmentation on typical PAHs-naphthalene biodegradation and analyzed the inhibition amendment mechanism of microbial biofilms in MECs. Compared with the control, the degradation efficiency of naphthalene with the nickel foam cathode supplied with bioaugmentation dosage realized a maximum removal rate of 94.5 ± 3.2%. The highest daily recovered methane yield (227 ± 2 mL/gCOD) was also found in the nickel foam cathode supplied with bioaugmentation. Moreover, the microbial analysis demonstrated the significant switch of predominant PAH-degrading microorganisms from Pseudomonas in control to norank_f_Prolixibacteraceae in MECs. Furthermore, hydrogentrophic methanogenesis prevailed in MEC reactors, which is responsible for methane production. This study proved that MEC combined with bioaugmentation could effectively alleviate the inhibition of PAH, with the nickel foam cathode obtaining the fastest recovery rate in terms of methane yield.

Organic-Inorganic Hybrid Crystal-Assisted Etching of Nickel Foam for the Collectively Exhaustive Electrochemical Performance of Oxygen Evolution Reaction.

In this work, an organic-inorganic hybrid crystal, violet-crystal (VC), was used to etch the nickel foam (NF) to fabricate a self-standing electrode for the water oxidation reaction. The efficacy of VC-assisted etching manifests the promising electrochemical performance towards the oxygen evolution reaction (OER), requiring only ~356 and ~376 mV overpotentials to reach 50 and 100 mA cm-2 , respectively. The OER activity improvement is attributed to the collectively exhaustive effects arising from the incorporation of various elements in the NF, and the enhancement of active site density. Furthermore, the self-standing electrode is robust, exhibiting a stable OER activity after 4,000 cyclic voltammetry cycles, and ~50 h. The anodic transfer coefficients (αa ) show that the first electron transfer step is the rate-determining step on the surface of NF-VCs-1.0 (NF etched by 1 g of VCs) electrode, while the chemical step involving dissociation following the first electron transfer step is identified as the rate-limiting step in other electrodes. The lowest Tafel slope value observed in the NF-VCs-1.0 electrode indicates the high surface coverage of oxygen intermediates and more favorable OER reaction kinetics, as confirmed by high interfacial chemical capacitance and low charge transport/interfacial resistance. This work demonstrates the importance of VCs-assisted etching of NF to activate the OER, and the ability to predict reaction kinetics and rate-limiting step based on αa values, which will open new avenues to identify advanced electrocatalysts for the water oxidation reaction.

Amorphous Co-Mo-P film on nickel foam: a superior bifunctional electrocatalyst for alkaline seawater splitting.

Seawater splitting is a compelling avenue to produce abundant hydrogen, which requires high-performance and cost-effective catalysts. Constructing bimetallic transition metal phosphides is a feasible strategy to meet the challenge. Here, an amorphous Co-Mo-P film supported on nickel foam (Co-Mo-P/NF) electrode is developed with bifunctional properties for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline seawater. Corresponding results indicate that the introduction of Mo can improve the active sites and regulate the intrinsic activity. Such a Co-Mo-P/NF behaves with prominent electrocatalytic activity towards both HER and OER, demanding low overpotentials of 193 and 352 mV at 100 mA cm‒2in alkaline seawater, respectively. Furthermore, the assembled electrolyzer demands a pronounced overall seawater splitting activity with a low cell voltage of 1.76 V to deliver 100 mA cm-2presenting excellent durability without obvious attenuation after 24 h continuous stability test. This work expands the horizon to develop transition metal-phosphorus electrocatalysts with robust and efficient activity for overall seawater splitting.

Binary Ni-Fe layered double hydroxide on flexible nickel foam for the wide-range voltammetric detection of fibrinogen in simulated body fluid.

Fibrinogen, a circulating glycoprotein in the blood, is a potential biomarker of various health conditions. This work reports a flexible electrochemical sensor based on Ni-Fe layered double hydroxide (Ni-Fe LDH) coated on Nickel foam (Ni-Fe LDH/NF) to detect fibrinogen in simulated human body fluid (or blood plasma). The nanoflakes like morphology and hexagonal crystal structure of LDH, synthesized via urea hydrolysis assisted precipitation technique, are revealed by scanning electron microscopy (SEM) and powder x-ray diffraction (PXRD) techniques, respectively. The fabricated sensor exhibits linearity in a wide dynamic range covering the physiological concentration, from 1 ng ml-1to 10 mg ml-1, with a sensitivity of 0.0914 mA (ng/ml)-1(cm)-2. This LDH-based sensor is found to have a limit of detection (LOD) of 0.097 ng ml-1and a limit of quantification (LOQ) of 0.294 ng ml-1(S/N = 3.3). The higher selectivity of the sensor towards fibrinogen protein is verified in the presence of various interfering analytes such as dopamine, epinephrine, serotonin, glucose, potassium, chloride, and magnesium ions. The sensor is successful in the trace-level detection of fibrinogen in simulated body fluid with excellent recovery percentages ranging from 99.5% to 102.5%, proving the synergetic combination of 2D Ni-Fe layered double hydroxide and 3D nickel foam as a promising platform for electrochemical sensing that has immense potential in clinical applications.

Glucose and UA sensing based on Cu nanoparticle decorated Nif/GO flexible electrode.

A novel, green, and facile approach has been developed to construct an ultrasensitive flexible enzyme-less electrochemical sensor on the basis of chitosan and graphene oxide composites decorated with Cu nanoparticles supported on nickel foam (Nif/Cs/GO@Cu), in which GO functions as the intermediate between Nif and Cu nanoparticles. The Nif/Cs/GO@Cu sensing platform was successfully fabricated by the drop casting method to load Cs/GO onto Nif followed by an additionally electrodeposition to support Cu nanoparticles on Nif/Cs/GO. Impressively, the Nif/Cs/GO@Cu exhibited much higher electrocatalytic activity for glucose and UA oxidation as compared to that of Nif or Nif@Cu. For glucose and UA at about 0.6 V and 0.1 V (vs. Ag/AgCl), linearity could be obtained in the concentration ranges 5 µM-4 mM and 5-345 µM; the sensitivities were 16 and 2.5 µA µM-1 cm-2, and the detection limits 83 nM and 0.3 µM, respectively. The improved performance of the composite electrode was ascribed to the synergistic effect of Cu nanoparticles, Nif and GO, in which GO provides high electron conductivity and large surface area to prevent the agglomeration of Cu nanoparticles; Cu nanoparticles and Nif offer abundant active sites towards analytes oxidation. Additionally, the method was applied to determine both analytes successfully in blood serum samples with excellent recovery and also opens up an attractive route to potential applications of the flexible nickel foam-based electrochemical sensor.

Trimetallic metal-organic frameworks (Fe, Co, Ni-MOF) derived as efficient electrochemical determination for ultra-micro imidacloprid in vegetables.

The excessive use of imidacloprid in agricultural production leads to a large number of residues that seriously threaten human health. Therefore, the detection of imidacloprid has become very important. But how to quantitatively detect imidacloprid at ultra-low levels is the main challenges. In this work, trimetallic metal-organic frameworks Fe, Co, Ni-MOF (FCN-MOF) isin situprepared on nickel foam (NF) and then used to make an electrochemical sensor in the detection of imidacloprid. FCN-MOF exhibits the characteristics of ultra-micro concentration detection for imidacloprid with high specific surface area and rich active metal centers. The high conductivity and 3D skeleton structure of the NF electrode enhance the contact site with imidacloprid and promote the transmission of electrons efficiently. All results show that the prepared electrochemical sensor has the advantages of ultra-low detection limits (0.1 pM), wide linear detection ranges (1-5 × 107pM) and good sensitivity (132.91µA pM‒1cm‒2), as well as good reproducibility, excellent anti-interference ability, and fantastic stability. Meanwhile, the electrochemical sensor is used to determine imidacloprid in lettuce, tomato, and cucumber samples with excellent recovery (90%-102.7%). The novel electrochemical sensor is successfully applied to the ultra-micro detection of imidacloprid in vegetables, which provides a new way for the efficient monitoring of imidacloprid in agriculture.

Multimetallic CuCoNi Oxide Nanowires In Situ Grown on a Nickel Foam Substrate Catalyze Persulfate Activation via Mediating Electron Transfer.

In situ growth of nanostructures on substrates is a strategy for designing highly efficient catalytic materials. Herein, multimetallic CuCoNi oxide nanowires are synthesized in situ on a three-dimensional nickel foam (NF) substrate (CuCoNi-NF) by a hydrothermal method and applied to peroxydisulfate (PDS) activation as immobilized catalysts. The catalytic performance of CuCoNi-NF is evaluated through the degradation of organic pollutants such as bisphenol A (BPA) and practical wastewater. The results indicate that the NF not only plays an important role as the substrate support but also serves as an internal Ni source for material fabrication. CuCoNi-NF exhibits high activity and stability during PDS activation as it mediates electron transfer from BPA to PDS. CuCoNi-NF first donates electrons to PDS to arrive at an oxidized state and subsequently deprives electrons from BPA to return to the initial state. CuCoNi-NF maintains high catalytic activity in the pH range of 5.2-9.2, adapts to a high ionic strength up to 100 mM, and resists background HCO3- and humic acid. Meanwhile, 76.6% of the total organic carbon can be removed from packaging wastewater by CuCoNi-NF-catalyzed PDS activation. This immobilized catalyst shows promising potential in wastewater treatment, well addressing the separation and recovery of conventional powdered catalysts.

Preparing Pd/Sn modified nickel foam electrode for nitrate removal from aqueous solutions.

Nitrate pollution in ground water and surface water has been becoming a worldwide problem that poses a great challenge to steady water ecosystem and human health. Electrochemical reduction is a promising way to remove nitrate from water because of advantages. We prepared Pd/Sn modified nickel foam (NF) electrode according to a two-step electrodeposition method. The prepared NF-Pd/Sn electrode showed a micromorphology like "Karst Fengcong" with peaks, saddles and nadirs intertwined with each other. Pd0 and Sn0 were detected on the NF-Pd/Sn electrode and the mass ratio of Pd/Sn was 4.3/1. The NF-Pd/Sn electrode showed the highest reaction rate (kobs: 0.543 h-1) and removal efficiency (94%) under the condition of 100 mg N/L, 0.05 mol/L Na2SO4 and -1.6 V vs. Ag/AgCl sat. KCl. The highest N2-selectivity (100%) was reached under the condition of 100 mg N/L, 0.05 mol/L NaCl and -1.6 V vs. Ag/AgCl sat. KCl. The microstructure of NF-Pd/Sn electrode like "Karst Fengcong" could provide large specific surface area and more active sites for nitrate adsorption and electrocatalytic reduction in aqueous solution. The adsorption and the reduction reaction of nitrate on the surface of NF-Pd/Sn could increase the electric current response in the test system.

Flower-like Highly Open-Structured Binder-Free Zn-Co-Oxide Nanosheet for High-Performance Supercapacitor Electrodes.

Scientific research is being compelled to develop highly efficient and cost-effective energy-storing devices such as supercapacitors (SCs). The practical use of SC devices is hindered by their low energy density and poor rate capability due to the binding agents in fabricating electrodes. Herein, we proposed flower-like highly open-structured binder-free ZnCo2O4 micro-flowers composed of nanosheets supported in nickel foam (ZnCoO@NF) with improved rate capability up to 91.8% when current varied from 2 to 20 A·g-1. The ZnCoO@NF electrode exhibited a superior specific capacitance of 1132 F·g-1 at 2 A·g-1 and revealed 99% cycling stability after 7000 cycles at a high current density of 20 A·g-1. The improved performance of the ZnCoO@NF electrode is attributed to the highly stable structure of the micro/nano-multiscale architecture, which provides both the high conduction of electrons and fast ionic transportation paths simultaneously.

Structural design of cobalt phosphate on nickel foam for electrocatalytic oxygen evolution.

The elaborate design and synthesis of low-cost, efficient and stable electrocatalysts for the oxygen evolution reaction (OER), which may alleviate the current energy shortage and environment pollution, is still a great challenge. Herein, metal phosphonate precursors with controllable morphologies were synthesizedin situon the surface of nickel foam with different solvents, and could be easily converted into carbon- and nitrogen-doped cobalt phosphate through a calcination method. The OER catalytic performance of the final products was studied in detail. The results showed that the nanowire shaped samples of CoPiNF-800 synthesized with deionized water under hydrothermal conditions had the strongest electrochemical performance. They exhibited extraordinary catalytic activity with a very low overpotential of 222 mV at 100 mA cm-2, the smallest impedance and excellent electrochemical stability. These results not only demonstrate the possibility of preparing low-cost OER catalysts based on transition metal phosphate, but also aid our understanding of the controllable synthesis process of different morphologies.

Highly efficient electrochemical gas reduction on a three-dimensional foam electrode: mechanism and application for the determination of hazardous mercury in complex matrix.

For the first time a nickel foam electrode (NFE) is applied in the field of electrochemical vapor generation (EVG) to carry out the electrochemical vapor phase conversion of mercury. Systematical electrochemical and morphological research has demonstrated that the specific surface area of the NFE was several times larger than that of the metal/non-metal electrode with the same geometric size. At the same time, the 3D porous channel composed of multi-layer nickel wire ensures the full contact between reactant and interface. The evident enhancement of spectral signals on a Ni electrode (283%), compared with Pt (27%) and graphite (109%), confirmed that the NFE effectively enhances the yield of mercury reduction. The NFE exhibits low limit of detection (0.017 µg L-1) and a wide linear range (0.2-20 µg L-1) with recoveries of actual samples in the range 87.8-117% towards Hg2+. Although the NFE has no advantage in electronic transmission and catalytic performance, its excellent stability, especially anti-interference and other characteristics, is sufficient for the analysis of hazardous mercury in complex matrix including certified reference materials and real samples.

A nickel foam modified with electrodeposited cobalt and phosphor for amperometric determination of dopamine.

Considering the importance of dopamine (DA) detection for neuroscience and disease diagnosis, herein, an electrochemical sensor for dopamine is described. It is based on the use of a Ni-Co-P nanostructure fabricated on nickel foam via electrode position from cobalt chloride and ammonium phosphate for 10 min. Time-dependent experiments show the transformation of Ni-Co-P nanoparticles to spheres. The resulting electrode display excellent electrochemical response to DA. Figures of merit include (a) a working potential of 0.55 V (vs. Ag/AgCl); (b) an electrochemical sensitivity of 5262 µA mM-1 cm-2; (c) a wide linear range (from 0.5 to 2350 µM), and (d) a 1 µM detection limit. The outstanding electrochemical performance is explained by the synergistic effects of large surface area, improved electron transfer, presence of free binders, and the presence of three active components (nickel, cobalt and phosphonium ion). Graphical abstract A Ni-Co-P nanostructure was electrodeposited on nickel foam to obtain an electrochemical sensor for amperometric determination of dopamine with outstanding performance.