High Electrochemical Active Surface Area Research Articles

Novel SeS2-loaded Co MOF with Au@PANI comprised electroanalytical molecularly imprinted polymer-based disposable sensor for patulin mycotoxin

An SeS2-loaded Co MOF and Au@PANI nanocomposite comprising the base matrix of the electrode was developed with electropolymerized molecularly imprinted polymer (MIP) consisting of p-aminobenzoic acid (PABA) and patulin (PT) to detect PT molecules based on the PT imprinted cavities. SeS2@Co MOF and Au@PANI were synthesized using hydrothermal synthesis and interfacial polymerization strategies, respectively. A suitable functional monomer to fabricate the MIP platform was selected using the density functional theory (DFT/M06-2X method). Higher electrochemical active surface area (0.985 cm2 which is 6.99 times higher than the bare SPE) and a lower charge transfer resistance (Rct = 27.8 Ω) at the MIP/Au@PANI/SeS2@Co MOF electrode was achieved based on the higher number of adsorptive sites and enhanced conductivity (electron transfer rate constant (ks = 3.24 × 10−3 s−1) of the sensing platform. The fabricated MIP sensor performance was studied in 10 mM PBS (pH = 6.4), where an improved detection limit (0.66 pM) for PT and a broad logarithmic linear dynamic range (0.001–100 nM) were both observed. The sensor possessed higher selectivity (Imprinting factor = 15.4 for PT), excellent reusability (%RSD of 10 cycles = 2.49%), high storage stability (6.7% lost after 35 days), and robust reproducibility (%RSD = 3.22%) The as-prepared MIP-based PT sensor was applied to detect PT in a real-time apple juice sample (10% diluted with PBS) with a recovery % ranging from 94.5 to 106.4%. The proposed sensor possesses great advantages in terms of cost-effectiveness, providing a simple detection strategy for long-term storage stability, and reversible cycle measurements.

Development of non-stoichiometric hybrid Co3S4/Co0.85Se nanocomposites for an evaluation of synergistic effect on the OER performance

Water electrolysis powered by renewable energy sources to produce green hydrogen is a very promising and sustainable alternative to fossil fuels, as well as one of the best approaches for significantly reducing carbon footprints and controlling pollution. In this study, novel hybrid non-stoichiometric nanocomposite Co3S4/Co0.85Se electrocatalyst materials were synthesized using a simple and one-pot eco-friendly hydrothermal method. The as-prepared samples were characterized using X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) for structural features. Crystalline phases of Co3S4, Co0.85Se, and mixed phases in the hybrid samples were confirmed through XRD. Uniformly distributed agglomerated nanoparticles (30-80 nm) of Co3S4, clearly distinguishable nanoaggregates (20-90 nm) of Co0.85Se, and nanoflakes covered with nanoparticles (30-150 nm) of Co3S4/Co0.85Se were confirmed by FESEM. The synergistic effects of the hybrid nanocomposite due to the combination of Co3S4 (containing two different oxidation states of cobalt) and non-stoichiometric Co0.85Se, was investigated towards the oxygen evolution reaction (OER). The electrocatalytic studies confirmed that the Co3S4/Co0.85Se electrocatalyst exhibited a low overpotential of 362 mV @ +30 mA.cm−2 towards the OER in an alkaline solution in comparison with Co3S4 and Co0.85Se electrocatalysts. Furthermore, a low overpotential of 1.59 V at a high current density and a high electrochemical active surface area (ECSA) of 210 cm2 was achieved due to the combined effects of chemical coupling between the Co3S4 and Co0.85Se. Chronoamperometric studies revealed excellent stability of the hybrid nanocomposite samples with negligible changes in the overpotential, even after 30 hours of testing. The synergetic effect of cobalt chalcogenides due to the nanoscale interaction was confirmed by the enhanced electrocatalytic activity.

Electrocatalytical Application of Platinum Nanoparticles Supported on Reduced Graphene Oxide in PEM Fuel Cell: Effect of Reducing Agents of Dimethlyformamide or Hydrazine Hydrate on the Properties

AbstractTwo kinds of reduced graphene oxide (rGO) were synthesized with the reducing agents of either dimethylformamide (DMF) or hydrazine hydrate (HYD). The decoration of platinum nanoparticles (Pt NPs) over these materials was provided by microwave irradiation (MWI) method. Detailed physical and electrochemical measurements were carried out. Based on the electrochemical results of both catalysts, it is not surprising the achievement of higher electrochemical active surface area (ECSA), higher oxygen reduction reaction (ORR) activity, higher electron transfer number, lower charge transfer resistance and higher fuel cell performance with the Pt/rGO (DMF) catalyst which surpasses Pt/rGO (HYD) in many ways.

Shelling with MoS2: Functional CuS@MoS2 hybrids as electrocatalysts for the oxygen reduction and hydrogen evolution reactions

• Wrapping of the cores with the shell was continuously varied and characterized. • Strained, defective shell and charge transfer from the core enable activation of the basal plane. • An optimal hybrid structure led to improved activity. • The hybrids are potent catalysts towards HER, and ORR. The development of noble-metal free electrocatalysts is of high importance for clean energy conversion applications. MoS 2 has been considered as a promising low-cost catalyst for the hydrogen evolution reaction (HER), however its activity is limited by poor conductivity and low abundance of active sites. Moreover, its suitability as an effective catalyst for other reactions, in particular the oxygen reduction reaction (ORR), was hardly explored to date. Herein, we show hybrid nanostructures of shelled CuS particles with MoS 2 layers, which produces several outcomes: The MoS 2 shell is strained and defective, and charge transfer from the core to MoS 2 occurs, enabling activation of the basal plane of MoS 2 . Changing the feed ratio of the precursors led to control over morphology, such that the wrapping of the cores with the shell was continuously varied and characterized. We found an optimal hybrid structure, which provided high electrochemical active surface area and fast charge transfer kinetics, leading to improved activity not only towards HER (overpotential of 225 mV at 10 mA cm −2 ), but also for the sluggish ORR (onset potential 0.87 V vs RHE).

Construction of porous core-shell MnCo2S4 microrugby balls for efficient oxygen evolution reaction

It is critical to rationally design highly efficient, stable, and cost-effective electrocatalysts for oxygen evolution reaction (OER). Herein, the porous core-shell MnCo2S4 microrugby balls are successfully synthesized via a two-step solvothermal method. Benefiting from the desired porous structure, strong electronic interaction and large specific surface area, it shows a small overpotential of 317 mV at a current density of 10 mA cm−2, a low Tafel slope of 73.7 mV dec−1 and robust stability, which is better than that of the corresponding metal oxides and commercial IrO2. The significantly enhanced OER performance of MnCo2S4 microrugby balls can be attributed to their high electrochemical active surface area and electrical conductivity. This work provides a new perspective to design and synthesize core-shell structured electrocatalysts.

Polyaniline-Decorated Carbon as Composite Carrier for Improving PtNi Catalyst Durability

Polyaniline (PANI) was synthesized on carbon cloth with a diffusion layer by an electrochemical technique and characterized by Fourier-transform infrared spectrometry, x-ray photoelectron spectroscopy, and scanning electron microscopy. PANI polymerized by a potentiostatic and a pulse potential method showed different morphologies. The former showed a granular shape and the latter a reticular structure. The reticular PANI was more suitable as a catalyst carrier based on the results of a cyclic voltammetry test. A PtNi catalyst electrodeposited on the reticular PANI-decorated carbon cloth (PtNi/PANI(PP)-C) had a smaller particle size and a homogeneous distribution. PtNi/PANI(PP)-C exhibited a higher electrochemical active surface area and better electrocatalytic activity according to the cyclic voltammetry and single cell polarization tests. Linear sweep voltammetry measurements indicated that PtNi/PANI(PP)-C showed excellent oxidation-reduction reaction activity through a four-electron transfer pathway. The results of an accelerated durability test showed that the performance degradation of PtNi/PANI(PP)-C was slower than that of PtNi/C. The reticular PANI-decorated carbon carrier improved the electrochemical activity and durability of the catalyst.

Modification of thermally reduced graphite oxide and molybdenum disulfide by solution plasma for hydrogen evolution reaction

Thermally reduced graphite oxide and molybdenum disulfide (TRGO@MoS2) is synthesized and modified by using solution plasma for hydrogen evolution reactions (HER). The HER performance of TRGO@MoS2 increased with the plasma treatment time until 10 h and then saturated. Low overpotential of −64 mV at 10 mAcm−2 with a small Tafel slope of 32 mVdec−1 for HER, which is comparable to 30 mVdec−1 of platinum, was obtained in TRGO@MoS2 after 10 h of the plasma treatment. The high HER performance attributes to the higher electrochemical active surface area, lower impedance, and smaller crystalline size in comparison with the precursor, proving that the plasma treatment introduces active surface area with improved conductivity which is a major factor for the efficient HER performance.

Highly dispersed L10-PtZn intermetallic catalyst for efficient oxygen reduction

Highly active and durable electrocatalysts with minimal Pt usage are desired for commercial fuel cell applications. Herein, we present a highly dispersed L10-PtZn intermetallic catalyst for the oxygen reduction reaction (ORR), in which a Zn-rich metal-organic framework (MOF) is used as an in situ generated support to confine the growth of PtZn particles. Despite requiring high-temperature treatment, the intermetallic L10-PtZn particles exhibit a small mean size of 3.95 nm, which confers the catalysts with high electrochemical active surface area (81.9 m2 gPt−1) and atomic utilization. The Pt electron structure and binding strength between Pt and oxygen intermediates are optimized through ligand effect and compressive strain. These advantages result in ORR mass activity and specific activity of 0.926 A mgPt−1 and 1.13 mA cm−2, respectively, which are 5.4 and 4.0 times those of commercial Pt/C. The stable L10 structure provides the catalysts with superb durability; only a halfwave potential loss of 11 mV is observed after 30,000 cycles of accelerated stress tests, through which the structure evolves into a more stable PtZn-Pt core-shell structure. Therefore, the development of a Zn based MOF as a catalyst support is demonstrated, providing a synergy strategy to prepare highly dispersed intermetallic alloys with high activity and durability.

Support effect on electrocatalytic performance of methanol oxidation over platinum catalysts

Graphene oxide and carbon nanotubes supported Pt nanoparticles were successfully synthesized by wet chemical reduction method. The structures and methanol oxidation performance of the two catalysts were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy (Raman) and electrochemical workstation. The results show that graphene oxide supported Pt nanoparticles exhibits higher electrochemical active surface area, methanol oxidation activity and stability compared with carbon nanotubes. It is proposed that the well dispersed Pt on the graphene oxide plays an important role for the excellent performancefor methanol oxidation.

Tuning the Electronic Structures of Multimetal Oxide Nanoplates to Realize Favorable Adsorption Energies of Oxygenated Intermediates.

Highly active oxygen evolution reaction (OER) electrocatalysts are important to effectively transform renewable electricity to fuel and chemicals. In this work, we construct a series of multimetal oxide nanoplate OER electrocatalysts through successive cation exchange followed by electrochemical oxidation, whose electronic structure and diversified metal active sites can be engineered via the mutual synergy among multiple metal species. Among the examined multimetal oxide nanoplates, CoCeNiFeZnCuOx nanoplates exhibit the optimal adsorption energy of OER intermediates. Together with the high electrochemical active surface area, the CoCeNiFeZnCuOx nanoplates manage to deliver a small overpotential of 211 mV at an OER current density of 10 mA cm-2 (η10) with a Tafel slope as low as 21 mV dec-1 in 1 M KOH solution, superior to commercial IrO2 (339 mV at η10, Tafel slope of 55 mV dec-1), which can be stably operated at 10 mA cm-2 (at an overpotential of 211 mV) and 100 mA cm-2 (at an overpotential of 307 mV) for 100 h.

Integration of Marigold 3D flower-like Ni-MOF self-assembled on MWCNTs via microwave irradiation for high-performance electrocatalytic alcohol oxidation and oxygen evolution reactions

Fabrication of metal-organic frameworks (MOFs) on carbon nanostructure arrays is extremely challenging. Here, we successfully fabricated three-dimensional (3D) flower-like Ni-MOFs on multiwalled carbon nanotubes (MWCNTs) through a highly efficient and rapid microwave synthetic protocol and studied their applicability in electrocatalytic alcohol oxidation reaction (AOR) and oxygen evolution reaction (OER). Morphological studies using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) images suggested the formation of marigold-like Ni-MOF decorated on the MWCNTs. Surface coverage of Ni-MOF@CNT (1.11 × 10−7 mol g-1) was higher than that of the pristine Ni-MOF (9.35 × 10-8 mol g-1) electrocatalyst. The higher electrochemical active surface area (ECSA) of Ni-MOF@CNT (494.3 cm2) compared to the pristine Ni-MOF (203.5 cm2) electrocatalyst resulted in the availability of large active sites in the Ni-MOF@CNT to catalyze AOR and OER. Ni-MOF@CNT exhibited a higher electrooxidation performance in AOR than the pristine Ni-MOF and its OER activity was far superior.

Dynamic Soft Templating of Monolithic Au Thin Film Electrodeposited from Bicontinuous Microemulsion

Electrochemical deposition has been the preferred method to use for the soft templating of nanoporous metal thin film because of its low-temperature metallization processes, which prevent damage to the structures not only of soft templates, including self-assembled surfactants or copolymers, but also of the formed nanoporous metals. Recently developed soft-templating methods are based on the replication of highly ordered micelle assemblies composed of surfactants or copolymers. However, it is still difficult to achieve wide size control over 100 nanometers by soft templating, though such control is necessary for electrocatalytic or biosensing applications.We report on the fabrication of monolithic nanoporous gold (Au) thin films by electrodeposition in bicontinuous microemulsion (BME) as a dynamic soft template (Figure (a)). Au electrodeposition occurs only at the aqueous phase of BME, which has intertwined nanometer-ordered three-dimensional networks composed of aqueous and oil solution channels compartmentalized by surfactants and cosurfactants. The thermodynamically stable BME can be formed simply by “mixing” together of the components, and the solution/solution structure of BME could be controlled simply by changing the BME composition. We prepared three kinds of BME solutions, including water-rich BME (water/oil ratio: 66/34), oil-rich BME (33/67), and equally mixed BME (69/31), by mixing 5.00 mL of 1 M hydrochloric acid solution containing 50 mM tetrachloroaurate(III), 5.00 mL cyclohexane, 0.40 g sodium dodecyl sulfate (SDS), and different volumes of 2-methyl-2-butanol (470, 590, and 510 μL, respectively) as cosurfactants. Figure (b-d’) shows the top surface and cross-sectional FE-SEM images of the resultant gold thin film electrodeposited onto sputtered Au film at -0.30 V vs. Ag/AgCl for 300 sec in (a) oil-rich BME, (b) equally mixed BME, and (c) water-rich BME, respectively. The resultant Au films each had a unique monolithic nanostructure grown vertically to the electrode surface. The characteristic ligament diameters of these films increased from 40 to 200 nm as the aqueous solution content increased. These results clearly indicate that BME no doubt behaved as a soft template and successfully demonstrate that structural control can be easily achieved by changing the BME solution/solution structure. In the case of equally mixed BME, we also confirmed that the ligament axial length was controllable between 180 and 650 nm by changing the electrodeposition time from 200 to 400 s. The cross-sectional observation of all the films revealed that there were no side pores even though BME had a reticulated solution structure on the order of 100 nm or less. This indicates that monolithic BME structures changed continuously during electrodeposition depending on the film surface morphology and acted as dynamic soft templates.We conducted voltammetric experiments to assess surface characteristics such as electrochemically active surface area (ECSA), exposed facets, and electrocatalytic activity. The apparent electrode area of each Au film was defined by putting insulating tape with a 2-mm-diameter hole on the electrode surface. The linear sweep voltammetry after forming a fully oxidized surface in 0.5 M H2SO4 solution revealed that the ECSA of the monolithic nanoporous Au film electrodeposited in equally mixed BME for 300 s was 4.2 times greater than that with the sputtered Au film (before electrodeposition). The cyclic voltammetry in the same solution revealed that the oxidation potential of the main peak current of the monolithic nanoporous Au thin film was lower (+1.08 V vs. Ag/AgCl) than that of sputtered Au thin film (1.29 V). These results indicate that the existence of well-exposed {100} facets and/or dominant step/kink sites at the monolithic nanoporous Au thin film probably derived from vertically grown, highly curved nanostructures. As a test reaction, the methanol oxidation reaction (MOR) was used to investigate the electrocatalytic performance of electrodeposited nanoporous Au films. The cyclic voltammetry obtained in the 0.5 M KOH aqueous solution in the absence and presence of 1 M methanol resulted in a 1.9 times larger peak top current (446 μA cm-2 app) at the monolithic nanoporous Au film than that of sputtered Au film due to high ECSA. Interestingly, the onset potential of MOR at the monolithic nanoporous Au film was -0.58 V, which is 0.20 V more negative than that at the sputtered Au film; this might derive from the {100} facets and/or the step/kink structure of the nanoporous Au film. Figure 1

Preparation of boron-carbide-supported iridium nanoclusters for the oxygen evolution reaction

Reducing the iridium loading for the oxygen evolution reaction (OER) is one of the main challenges of polymer electrolyte membrane water electrolysis (PEMWE). This study introduces grape-like iridium nanoclusters supported on boron carbide (B4C) which increase iridium utilization compared to a non-supported iridium catalyst. A simple chemical reduction method with NaBH4 as a reducing agent was used to synthesize iridium nanoclusters on B4C. TEM images indicated that grape-like iridium nanoclusters were successfully dispersed on the B4C support. The catalytic performance of Ir/B4C was better than that of a commercial catalyst. To reach a current density of 10 mA/cm2, the overpotential of Ir/B4C was less than that of the commercial catalyst by 32 mV. Ir/B4C also has a mass activity 2.55 times higher than that of the commercial catalyst at 1.55 V. These improvements are attributed to the high electrochemical active surface area, the weak adsorption strength of oxygen, and the presence of Ir(OH)4 on the surface. The durability of Ir/B4C is comparable to that of the commercial catalyst at 1 mA/cm2 for 15 h and higher at 10 mA/cm2 for 3 h. B4C may weaken the oxidative dissolution of iridium by transferring electrons even though the high electrochemical surface area of iridium in Ir/B4C may reduce its durability.

β-Mo2C/MoO2 heterostructures for hydrogen evolution reaction: Morphology and catalytic activity regulated by heteroatom doping

Improving the activity of non-noble metallic electrocatalyst for hydrogen evolution reaction (HER) is an important issue for hydrogen energy utilization. In this work, we reported a new strategy for morphology regulation of β-Mo2C/MoO2 heterostructure via heteroatom doping to enhance the electrocatalytic HER activity. Electron microscopy observations found that N and S doping resulted in nanosphere and nanorod morphology, respectively. Amongst the S doping catalyst (denoted as S@β-Mo2C/MoO2) exhibited remarkably improved electrocatalytic HER activity and stability as compared to the pristine β-Mo2C/MoO2 catalyst, whereas the N doping induced significant degradation of catalytic activity and stability. The mechanism investigations reveal that the nanorod morphology of S@β-Mo2C/MoO2 endows it lower charge transfer resistance, higher electrochemical active surface area and lower valence state of Mo species, which contributes positively and importantly to its better electrocatalytic HER activity.

Polypyrrole assisted synthesis of nanosized iridium oxide for oxygen evolution reaction in acidic medium

The application of electrochemical water splitting process in acidic medium is restricted by the lack of highly efficient and stable oxygen evolution reaction (OER) electrocatalyst. In this work, we report a facile soft template method to synthesize nanosized iridium oxide for electrocatalytic OER in acidic medium. The fabrication process involves thermal treatment of iridium complex and polypyrrole in air. The compositions and structures of the resulting catalytic materials are significantly influenced by the annealing temperature. The nanostructured iridium oxide synthesized at optimal 450 °C exhibits low overpotential (291.3 ± 6 mV) to reach 10 mA/cm2 current density towards OER, which is better than the commercial iridium oxide. Further investigation indicates that nanosized iridium oxide synthesized at 450 °C has high electrochemical active surface area to expose abundant accessible active sites, which can accelerate the OER rate. This method can also provide new guidance to prepare other metal oxide nanoparticles for various applications.

Synthesis of nitrogen-doped reduced graphene oxide and its decoration with high efficiency palladium nanoparticles for direct ethanol fuel cell

For the first time, reduced graphene oxide (RGO) and nitrogen doped RGO (N-RGO) are prepared by the electrochemical procedure and then decorates with palladium nanoparticles via a solvothermal method to obtain Pd/RGO and Pd/NRGO. The as-synthesized electrocatalysts are characterized by transition electron microscopy (TEM), x-ray photoelectron (XPS), energy dispersive spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FTIR) techniques. The bare RGO and NRGO electrodes are very active for the oxygen reduction reaction (ORR) and ethanol tolerance, providing the best performance in terms of tafel slope and onset potential. But, the resulting Pd/NRGO electrocatalyst shows outstanding electrocatalytic performance toward both ORR and ethanol oxidation reaction (EOR), including higher peak current density and low tafel slope than that of Pd/RGO, which can be related to high electrochemical active surface area of Pd/NRGO (53 m2 g−1) than that of Pd/RGO (41 m2 g−1). Finally, the fabricated anionic alkaline Membrane-electrode assemblies (MEAs) by using RGO, NRGO, Pd/RGO and Pd/NRGO are studied in single air-breathing direct ethanol fuel cell, as anode and cathode, with solutions of 4 M ethanol and 2 M KOH at room temperature.

Surface engineering of carbon selenide nanofilms on carbon cloth: An advanced and ultrasensitive self-supporting binder-free electrode for nitrite sensing

Large uptakes of nitrite have been proven to be detrimental to human health, therefore, the development of high-performance nitrite sensors is highly emergent. Herein, a carbon selenide nanofilms modified carbon fiber cloth (CSe2 NF/CC) electrode was obtained via in-situ synthesis to detect nitrite. The electrode integrates the collective merits of macroporous CC and pleated carbon selenide nanofilms, possessing a low overpotential of 0.83 V, a high electrochemical active surface area (EASA) of 5.39 cm2, great electrical conductivity, and fast charge transport as well as ion diffusion. The proposed electrode achieved a low limit of detection of 0.04 μmol L−1 (S/N = 3), a high sensitivity of 2048.56 μA mmol L−1 cm−2, excellent selectivity, and long-term stability. Additionally, the CSe2 NF/CC was successfully used for nitrite detection in different food samples such as pickled vegetables and sausage samples.

Self-supported Pt-CoO networks combining high specific activity with high surface area for oxygen reduction.

Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum-cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum-cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification.

Electrodeposition of Ni–Fe–Mn ternary nanosheets as affordable and efficient electrocatalyst for both hydrogen and oxygen evolution reactions

The synthesis of high performance and economical electrocatalysts in the process of overall water splitting is very important for the production of hydrogen energy and has become one of the most important challenges. Here, various Ni, Ni–Fe, Ni–Mn nanosheets and Ni–Fe–Mn ternary nanosheets were created using cost-effective, versatile and binder-free electrochemical deposition methods, and the electrocatalytic activity of various electrodes for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were investigated in an alkaline environment. Due to the high electrochemical active surface area due to the fabrication of nanosheets, the synergistic effect between different elements on the electronic structure, the high wettability due to the formation of nanosheets and the quick detachment of formed gasses from the electrode, the Ni–Fe–Mn nanosheets electrode showed excellent electrocatalytic activity. In order to deliver the 10 mA cm−2 current density in HER and OER processes, this electrode required values of 64 mV and 230 mV overpotential, respectively. Also, the stability test showed that after 10 h of electrolysis at a current density of 100 mA cm−2, the overpotential changes was very small (less than 4%), indicating that the electrode was excellent electrostatic stability. Also, when using as a bi-functional electrode in the full water splitting system, it only needed a cell voltage of 1528 V to deliver a current of 10 mA cm−2. The results of this study indicate a new strategy for the synthesis of active and stable electrocatalysts.

Fe doped metal organic framework (Ni)/carbon black nanosheet as highly active electrocatalyst for oxygen evolution reaction

To alleviate the sluggish oxygen evolution reaction (OER) kinetics, it's urgent to develop electrocatalysts with high activity and low cost. In this work, Fe doped metal organic frameworks (Ni)/carbon black composites were synthesized via a facile hydrothermal method. Benefiting from the direct use of metal organic frameworks (MOFs) for OER, numerous and highly dispersed active sites are exposed to the electrolyte and reactants. By regulating Ni/Fe ratios, a high electrochemical active surface area (ECSA) and high relative surface content of active Ni3+ species are obtained, which mainly contribute to the high OER activity. Besides, the introduced carbon black (CB) was found to enhance the charge-transfer efficiency of the electrocatalysts, which is also favorable for OER. The optimal Ni9Fe1-BDC-0.15CB electrocatalyst shows excellent OER activity with the low overpotential of ~290 mV at 10 mA cm−2 and the Tafel slope of ~76.1 mV dec−1, which is comparable to RuO2 and other MOFs-based OER electrocatalysts reported in recent years.