Consecutive Cyclic Voltammetry Research Articles

CuNi2O4/MWCNTs nanocatalyst for methanol and ethanol electro-oxidation

The widespread use of cheap and efficient catalysts in energy storage and production in electrochemical processes led our research team to the synthesis and evaluation of CuNi2O4/MWCNTs nanocatalyst for alcohol oxidation. Nanocatalyst was characterized in terms of structure and morphology by X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDAX). The ability of CuNi2O4/MWCNTs was evaluated with cyclic voltammetry (CV) and linear sweep voltammetry (LSV) analyses in the oxidation process of methanol and ethanol alcohols in alkaline media. The optimal concentration of methanol and ethanol for CuNi2O4/MWCNTs and CuNi2O4 was obtained to investigate the methanol oxidation reaction and ethanol oxidation reaction processes. The mechanism of these processes was also evaluated in detail. The stability of both nanocatalysts was investigated by performing several consecutive CVs and in 3600 s by chronoamperometric analysis. The results showed the good stability of this catalyst. The synergistic effect of placing CuNi2O4 on the surface of carbon nanotubes improved the oxidation process of methanol and ethanol. In general, the proposed catalyst can be an efficient, stable, and cheap option and at the same time very stable for use in alcohol fuel cells.

1,2,4-Triazole-Ligand-based Iridium(III) complex and its use in blue phosphorescent organic light-emitting diodes

Organic light-emitting diodes (OLEDs) play a key role in modern flexible displays. Although stable and efficient red- and green-emitting phosphors have been developed, the applications of blue emitters are limited due to their poor chemical and electrochemical stability, and thus, they require further development. Herein, we report the preparation and full characterization of IrTrz, a 3-methyl-5-phenyl-1H-1,2,4-triazole-ligand-based facial-homoleptic iridium complex. Single-crystal X-ray diffractometry results suggested that the complex is a facial isomer with C3 point symmetry. The complex exhibited a blue emission band centered at ∼450 nm in both solution and the film state at ambient temperature; moreover, it showed a very narrow full-width at half maximum value (55 nm) and a moderate photoluminescence quantum yield (33%). The complex showed high thermal stability, with 5%-weight-loss and glass-transition temperatures of 324 and 210 °C, respectively. Consecutive cyclic voltammetry measurements revealed outstanding electrochemical stability of the complex. Therefore, multilayer phosphorescent OLEDs that use IrTrz as the blue emitter were fabricated with two types of host material: (3,3′-di(9H-carbazol-9-yl)-1,1′-biphenyl (mCBP) and 9-(dibenzo[b,d]thiophen-4-yl)-9H-3,9′-bicarbazole (4DBTCz)). In particular, the 4DBTCz-based devices exhibited low turn-on voltages (∼5.0 V) and high external quantum efficiencies (>11%) with a Commission Internationale de l’Eclairage y-coordinate of 0.2. Moreover, the devices demonstrated stable operational lifetimes that exceeded 690 h (for mCBP) and 390 h (for 4DBTCz) at 100 cd/m2. Therefore, we believe that the 1,2,4-triazole-ligand-based Ir(III) complex is a promising blue-phosphorescent emitter material for applications in stable and efficient OLED devices.

Electrical Field-Induced Hydrogen Generation at Electrochemically Grown Catalyst-Free Carbon Fiber Microstructures

Simple cathodic treatments, conducted in an aqueous acidic solution and at hydrogen evolving potentials, are shown to form truncated cone-like microstructures on the surface of carbon fiber paper (CFP) electrodes. An effective ∼32-fold increase of effective surface area was determined for CFPs after consecutive cyclic voltammetry (CV) and chronopotentiometry (CHR) treatments as compared to untreated CFP. Moreover, this is accompanied, as determined by XPS and EIS techniques, by changes in surface chemistry toward a more dominating sp2 nature of the C–C bonds and a significant (∼270-fold) decrease of charge transfer resistance. Electrochemical observations, as well as numerical simulations, indicate that high electrical fields near the microstructures, arising from an applied potential on treated electrodes, increase local H+ concentrations, which can reach values in the order of ∼40- to ∼70-fold that of the bulk H+ concentration. This is shown to have a significant impact on the performance of the CFP-treated electrodes toward the important energy-related hydrogen evolution reaction (HER); the current density at −0.70 V vs RHE for a CV-treated CFP electrode can reach a value 70-fold higher than that of an untreated one (10.5 and 0.15 mA cm–2, respectively). An additional 10-fold current density increase related to effective surface increase can be achieved by a consecutive CHR treatment. Long-term stability was determined for such treated electrodes during H2 generation for 20 h in 1 M H2SO4 at a constant applied current density of 5.0 mA cm–2. It is anticipated that further development of the present concepts may lead to possible future use of such simply obtained structured electrodes in electrochemical energy conversion/storage devices.

High-capacity MnCo2O4/NiCo2O4 as electrode materials for electrochemical supercapacitors

In recent decades, investigations on eco-friendly energy storage devices to cope with the energy crisis and alleviate environmental pollution have garnered immense attention. Moreover, supercapacitors commercialization requires finding affordable, stable electrode nanomaterials of sufficient capacitance. Recent research has shown new hope for using two metal oxides together. Therefore, the present study introduced MnCo2O4/NiCo2O4 with star morphology on a nickel foam substrate as a cost-effective electrode for the first time. This electrode was prepared by a simple hydrothermal method in which MnCo and NiCo2O4 were deposited on nickel foam via a two-stage synthesis process. Furthermore, a particular star-like morphology was obtained by altering the synthesis temperature and time. The galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were employed to assess the electrochemical properties of the electrodes by the three-electrodes system in a 3 M KOH solution. The synergistic effect of MnCo2O4 with NiCo2O4 led to an excellent capacitance of 1276 F/g and stability of 96.4% following 5000 consecutive CV cycles. Finally, the NiCo2O4/MnCo2O4 supercapacitor application was investigated in an asymmetric supercapacitor as the positive electrode, with rGO being the negative electrode. The results indicated satisfactory performance with a power density of 540 W/kg and an energy density of 68 W h//kg.

CeO2-NiO-rGO as a nano-electrocatalyst for methanol electro-oxidation

This study provides the methanol oxidation capability of two nanocatalysts, CeO2-NiO (CN) and CeO2-NiO-rGO (CNR), synthesized by a cost-effective hydrothermal method. The synergistic effect of compositing CeO2-NiO with reduced graphene oxide was evaluated. These synergic effect makes a good electrochemical active surface area and suitable electrical conductivity for catalyst. In addition, rGO with good electrical conductivity revealed considerable improvement in the methanol oxidation reaction performance of the catalyst. The cyclic stability measurements of CeO2-NiO-rGO showed a high retention ability of 96% in 500 consecutive cyclic voltammetry cycles, while the stability of CeO2-NiO in the same number of cycles is about 93%. The complementary methanol oxidation process results indicated an oxidation current density up to 49.5 and 68.5 mA cm−2 for CN and CNR at a scan rate of 20 mV s−1, respectively. The proposed catalyst can be considered as an attractive, stable, and inexpensive candidate in the field of methanol oxidation to use in methanol fuel cells.

Galvanic replacement of Pt by Cu to synthesize highly active and durable Pt@Cu/C anode as oxygen evolution reaction catalyst

In this research, a two-step procedure was applied to prepare Pt/Cu/C titanium-supported anode as an oxygen evolution reaction (OER) catalyst. First, the copper nanoparticles with an average particle size of 20 nm were chemically reduced on carbon Vulcan powder (Cu/C). Then, galvanic replacement of Pt by Cu was performed by immersing Cu/C powder in a platinum solution. Finally, the catalyst ink was brushed over the activated titanium substrate using Pt/Cu/C powder and polyvinylidene difluoride (PVDF) in N-methyl-2-pyrrolidone (NMP) solvent. The effect of different factors, such as synthesis temperature and platinum loading on the catalytic properties of nanoparticles, including electrochemical surface area (ECSA), activity, stability, and durability for the OER, were evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry, and consecutive CV. The results showed that the platinum loading level of 0.5 mg/cm2 and the synthesis temperature of 60 °C provide the best catalytic performance. Also, compared to the commercial electrodes of iridium oxide and ruthenium oxide with the same noble metal loading, higher activity is obtained for Pt/Cu/C electrode than the two mentioned electrodes. In addition, from a lifetime standpoint, the Pt/Cu/C electrode showed higher stability than the commercial ruthenium oxide electrode.

Interface engineering of Ni/NiO heterostructures with abundant catalytic active sites for enhanced methanol oxidation electrocatalysis

Designing efficient and stable non-noble metal electrocatalysts with good performance in reaction kinetics is desirable yet challenging for the study of methanol oxidation reaction (MOR). Herein, we have reported well-defined nanoscale nickel/nickel oxide (Ni/NiO) heterostructures supported by a three-dimensional (3D) porous graphene network (RG) via a delicate interface engineering technique. The as-prepared 3D Ni/NiO/RG composites achieve outstanding catalytic activity (79.5 mA cm−2/1262.1 mA mg−1) for MOR in alkaline solution, outperforming most reported non-precious catalysts. A combined experimental and computational investigation shows that such a good performance benefits from the specific Ni/NiO interface, which not only bears abundant accessible active sites but also improves the energetics of MOR. Moreover, this interface contributes to favorable kinetic and improved structural stability during electrocatalysis, ensuring superior catalytic performance after 1000 consecutive cyclic voltammetry tests for MOR. Our work demonstrates the potential of interface engineering in the rational design of efficient precious-metal-free electrocatalysts.

Engineering of GO/MWCNT/RuO2 ternary aerogel for high-performance supercapacitor

It is of great importance to fabricate high-performance electrode materials via a facile fabrication pathway to be utilized in energy storage systems, specifically in supercapacitors. Herein, ruthenium(IV) oxide (RuO2) was decorated onto the nanocomposite of graphene oxide (GO) and functionalized multi-walled carbon nanotubes (MWCNT) via straight forward production pathway for the first time, and the resultant nanostructure was then characterized physicochemically via x-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscope (FESEM), and energy dispersive X-ray analysis (EDX). The fabricated nanostructure was employed as the electrode material to develop a high-energy symmetrical supercapacitor cell. The electrochemical performance of the as-assembled supercapacitor was assessed by cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) techniques. The highest specific capacitance was achieved as 514.9F.g−1 at a current density of 0.5 A.g−1. Moreover, even at a high current density of 10.0 A.g−1, the specific capacitance value was computed still as high as 329.3F.g−1. The superior capacitance retention feature (94.38 % at the end of 5,000th consecutive CV cycles) revealed the outstanding electrochemical activity of the electrode material. The attained energy density of 37.96 W.h.kg−1 (at a power density of 8.33 kW.kg−1) implied the potential application of the proposed supercapacitor cells as a high-energy system.

MWCNT/Ruthenium hydroxide aerogel supercapacitor production and investigation of electrochemical performances

In this study, the material obtained from the sonication of the double-walled carbon nanotube and ruthenium chloride was produced as an aerogel. Then, symmetrical supercapacitor devices were made using them, and their electrochemical properties were investigated. XRD and FTIR were used in the structural analysis of the aerogel, STEM in surface images, and elemental analyses in EDX. Electrochemical analysis was performed by galvanostat/potentiostat. From the cyclic voltammetry analysis, the highest specific capacitance for MWCNT/Ruthenium hydroxide aerogels was achieved as 423 F/g at 5 mV/s. On the other hand, the corresponding values calculated from the charge–discharge curves were found to be 420.3 F/g and 319.9 F/g at the current densities of 0.5 A/g and 10.0 A/g, respectively. The capacitance retention of as-synthesized aerogel was 96.38% at the end of the 5000 consecutive consecutive cyclic voltammetry cycles.

Effect of Pt-Ni deposition sequence on the bimetal-modified boron-doped diamond on catalytic performance for glucose oxidation in neutral media

• The PtNi modified boron-doped diamond were fabricated to detect glucose at neutral pH. • Electrodeposition sequences effect on electrocatalytic properties of Pt-Ni bimetals. • The PtNi biemetal prepared by co-deposition had the highest stability and sensitivity. The growing number of people with diabetes has gained extensive attention over the past decades, driving the need to develop sensitive glucose sensors to monitor glucose levels under physiological pH conditions. Bi-metal (Pt-Ni) modified boron-doped diamond (BDD) electrodes were reported to allow a continuous and stable response measurement of glucose under neutral pH conditions. Effects of the electrochemical deposition sequence on the morphology and electrocatalytic properties of the Pt-Ni bimetal were systematically investigated. Electrochemical tests showed that the Pt-Ni bimetal clusters prepared by the co-deposition (one step) method had higher stability and sensitivity for the glucose detection than those prepared by the two-step deposition method. The PtNi-BDD increased around 19% of the initial signal after 200 consecutive cyclic voltammetry cycles for 2400 s, while as a comparison, Ni/Pt-BDD and Pt-BDD increased 44% and 40% for 2400 s, respectively. In addition, the sensitivity of PtNi-BDD was obtained to be 110.4 μA cm −1 mm −1 in the range of 2–12 mM glucose concentration, around 6.1, 15.5, and 6.0 times higher than that of Pt/Ni-BDD, Ni/Pt-BDD, and single metal Pt, respectively.

Electrochemical deposited amorphous FeNi hydroxide electrode for oxygen evolution reaction

The electrodeposition approach is significant in electrode fabrication for practical application. Herein, the electrodeposited amorphous NiFe hydroxide species for oxygen evolution reaction (OER) in water splitting reaction is demonstrated by revealing the synergistic effect influenced by the support electrode of Fe and Ni foil and the contents of Fe and Ni in the electrolyte. All the electrodeposited samples have an amorphous structure and similar profiles of binding energy and chemical states for Fe and Ni as characterized by the spectroscopic techniques. While the support effect and Fe/Ni synergistic effect are indeed observed for the varied catalytic performances observed for the different electrodes; the Ni foil supported catalyst exhibits much higher performance than that of the Fe foil supported catalyst, and the different redox potentials of Ni species in the different Fe/Ni electrode resulting from the Fe–Ni synergism are observed in the cyclic voltammetry curve analysis. The surface roughness and the electrochemical surface area are also influenced by the support effect and the Fe/Ni ratio in the plating electrolyte. The optimal electrode shows a very low overpotential of ∼200 mV to reach 10 mA cm−2, and very high catalytic stability by the consecutive cyclic voltammetry measurements and 20 h stability test. Though it has the largest electrochemical surface area, the highest catalytic efficiency for these active sites is also indicated by the specific activity and turnover frequency polarization curves. The current work shows the effective experience for the electrodeposited Fe/Ni based catalysts in large-scale fabrication, which can be more practical for hydrogen generation in the alkaline water electrolysis.

Evaluation of Electrocatalytic Activity of Noble Metal Catalysts Toward Nitrogen Reduction Reaction in Aqueous Solutions under Ambient Conditions.

Electrochemical nitrogen reduction reaction (NRR) is intensively investigated by researchers for its potential to be the next-generation technology to produce ammonia. Many attempts have been made to explore the possibility of electrochemical ammonia production catalyzed by noble metals. However, the produced ammonia in most reported cases is in ppm level or even lower, which is susceptible to potential contaminants in experiments, leading to fluctuating or even contradictory results. Herein, a rigorous procedure was adopted to systematically evaluated the performance of commercial noble metal nanocatalysts toward NRR. No discernible amount of ammonia was detected in either acidic or alkaline solutions. Further, nitrogen-containing contaminants in catalysts that might cause false positive results were detected and characterized. An effective way to remove pre-existing pollutants by consecutive cyclic voltammetry scan was proposed, helping to obtain reliable and reproducible results.

Three-dimensional bundle-like multiwalled carbon nanotubes composite for supercapacitor electrode application

Bundle-type mutil-walled carbon nanotubes (MWCNTs) composite electrode is the first investigation and publication for the supercapacitor application. According to the thermogravimetric analysis results, as-synthesized BCNTs are considered as the electrode materials for supercapacitors and electrochemical double-layer capacitor in this study. The Brunauer–Emmett–Teller specific surface area of as-prepared bundled carbon nanotubes (BCNTs) is 95.29 m2/g given to a type III isotherm and H3 hysteresis loops. Slow scanning rates promote and enhance to achieve high Cb because of the superior conductivity of CNT bundles and one side close-layered Ni/Mg/Mo alloy inside the BCNT-based electrode and facile electron diffusivity between electrolyte and electrode. The specific capacitance Cs (1,560 F/g) is nearly equal to the maximum specific capacitance, which the BCNT-based composite electrode can actually be able to charge or fill in. The maximum energy density value is 195 Wh/kg with corresponding power density values of 0.21 kW/kg. Furthermore, the active 3D BCNTs material fabricated electrode enhances to contact the electrolyte directly and decreases the ion diffusion limitation. Electrochemical impedance spectroscopy spectrum summarized as the low-frequency area controls by mass transfer limitation, and the high-frequency area dominates by charge transfer of kinetic control. After 2,000 consecutive cyclic voltammetry sacnings and galvanostatic charge-discharge cycles at a current density of 1.67 A/g performs, the specific capacitance retentions of 3D BCNTs electrodes achieved 128.2 and 77.3%, respectively. Three-dimensional BCNT composite electrodes exhibit good conductivity and low charge transfer resistance, which is beneficial to fast charge transfer between the BCNTs electrode materials and electrolytes.

Higher-voltage asymmetric-electrolyte metal-air batteries

Higher-voltage asymmetric-electrolyte metal-air batteries

Switching of the ion exchange behaviour of PEDOT thin films during a potential cycling: An electrochemical atomic force microscopy study

Thickness variations of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films placed under potential conditioning were measured with the help of electrochemical atomic force microscopy (EC-AFM). In this purpose, in-situ AFM operating in the contact mode was coupled with either cyclic voltammetry (CV) or advanced cyclic voltammetry (AdCV). A PEDOT functionnalized platinum electrode was used simultaneously as a sample for in-situ AFM measurements and a working electrode in a usual three electrode electrochemical setup. PEDOT films were electrodeposited with the help of the CV technique from lithium perchlorate aqueous solutions. From these EC-AFM investigations, brand new PEDOT films were found to be anion exchangers, in good agreement with conclusions of investigations reported in literature. Unexpectedly, PEDOT films having undergone a comprehensive electrochemical cycling (i.e. an electrochemical aging) in a potential range encompassing narrowly their redox process by using tens of CV or AdCV potential cycles behave as cation exchangers. Such observation strongly suggests that the electrochemo-mechanical and ion exchange behaviours of PEDOT can be both switched by simply using a potential cycling. Interestingly, the initial steps of this switching process were observed on a brand new PEDOT film during 26 consecutive CV scans. In the course of this process still ongoing at the end of the 26th cycle, a second swelling peak appears and grows progressively beside the initial swelling peak attributed to an anion exchange behaviour. This leads to a dual ion exchange behaviour for the resulting PEDOT film within the explored potential range. Indeed, this new swelling peak can be attributed to a cation exchange behaviour from the comparison of the potential dependant chronothicknograms and corresponding voltathicknograms with those obtained previously in this work.

MoS2–ReS2/rGO: A novel ternary hybrid nanostructure as a pseudocapacitive energy storage material

In this study, three 2D materials include molybdenum disulfide (MoS2), rhenium disulfide (ReS2), and reduced graphene oxide (rGO) are synthesized and then hybridized in the form of a ternary hybrid (MoS2-ReS2/rGO) for pseudocapacitor electrode materials. The structure of materials is confirmed with X-ray diffraction analysis (XRD), Raman spectroscopy. The morphology of the synthesized materials is evaluated with a scanning electron microscope (SEM) and transmission electron microscopy (TEM) images. The electrochemical tests of cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) are performed to investigate the electrochemical performance of electrodes. MoS2–ReS2/rGO shows a specific capacitance of 949 F/g and also very good stability of 92% after 5000 consecutive CV cycles. According to the significant synergistic effect between hybrid components, the MoS2-ReS2/rGO electrode can be considered as a good electrode for use in the energy storage field.

Fast and stable K-ion storage enabled by synergistic interlayer and pore-structure engineering

Carbon-based material has been regarded as one of the most promising electrode materials for potassium-ion batteries (PIBs). However, the battery performance based on reported porous carbon electrodes is still unsatisfactory, while the in-depth K-ion storage mechanism remains relatively ambiguous. Herein, we propose a facile “in situ self-template bubbling” method for synthesizing interlayer-tuned hierarchically porous carbon with different metallic ions, which delivers superior K-ion storage performance, especially the high reversible capacity (360.6 mAh·g−1@0.05 A·g−1), excellent rate capability (158.6 mAh·g−1@10.0 A·g−1) and ultralong high-rate cycling stability (82.8% capacity retention after 2,000 cycles at 5.0 A·g−1). Theoretical simulation reveals the correlations between interlayer distance and K-ion diffusion kinetics. Experimentally, deliberately designed consecutive cyclic voltammetry (CV) measurements, ex situ Raman tests, galvanostatic intermittent titration technique (GITT) method decipher the origin of the excellent rate performance by disentangling the synergistic effect of interlayer and pore-structure engineering. Considering the facile preparation strategy, superior electrochemical performance and insightful mechanism investigations, this work may deepen the fundamental understandings of carbon-based PIBs and related energy storage devices like sodium-ion batteries, aluminum-ion batteries, electrochemical capacitors, and dual-ion batteries.

Ruthenium Oxide Hexacyanoferrate as an Effective Electrode Modifier for Amperometric Detection of Iodate and Hydrogen Peroxide

Ruthenium oxide hexacyanoferrate (RuOHCF) film was electrochemically deposited on to a glassy carbon (GC) surfaceusing consecutive cyclic voltammetry as a facile and green synthetic strategy. The electrochemical behaviour and electrocatalytic properties of the modified electrode Ru?HCF/GC were evaluated with regards to electroreduction of hydrogen peroxide and iodate in a strong acidic medium (pHs 1.0-2.0) by using different electrochemical techniques, including cyclic voltammetry and amperometry at a constant potential. Electrochemical studies indicated that Ru?HCF/GC possess a high catalytic activity in both studied reactions, fast response and good reproducibility of the current signal. The Ru?HCF/GC exhibits enhanced electrocatalytic behaviour compared with other modified electrodes reported before. The simple and reproducible procedure for electrode fabrication, the wide linear range, anti-interference performance and long-time stability of the Ru?HCF/GC make it a promising sensing material for practical quantitative determination of hydrogen peroxide and iodate. Remarkably, the reported modified.

In Situ Monitoring of Collision and Recollision Events of Single Attoliter Droplets via Single-Entity Electrochemistry.

We describe a simple method for real-time observation of collision and recollision behavior of a single aqueous attoliter droplet in an organic solvent through single-entity electrochemistry. The dynamics and morphology of the droplet after the collision event at the Au ultramicroelectrode (Au-UME) were monitored by consecutive cyclic voltammetry and amperometric current-time measurements. By sequentially applying oxidative potential and reductive potential at the Au-UME in the presence of attoliter droplets containing reversible redox species (e.g., ferrocyanide), we successfully detected the oxidative collision spike and its reductive recollision spike successively owing to the reversible redox reactions inside the droplet. Because the redox species was dissolved in a reduced form, the reductive collision spikes observed are the direct evidence that the water droplets colliding at the electrode surface are detached after the oxidation reaction. The collided droplet properties, such as size change and contact area, are also investigated and discussed.

Simultaneous Preparation and Functionalization of Ultrathin Few−layer Black Phosphorus Nanosheets and Their Electrocatalytic OER and HER Performance

AbstractA convenient liquid phase exfoliation method is reported here to prepare functionalized few−layer black phosphorus (BP) nanosheets by using succinic acid (SA) or L−ascorbic acid (L−AA) −assisted tip−ultrasonicated exfoliation. The thickness of the obtained nanosheets is about 2–2.5 nm, which is equivalent to 4–5 layers of BP atoms. And SA−BP−1 : 3 exhibits a best OER and HER performance in the group of SA−BP with different weight ratios, requiring an overpotential of 369.8 mV for OER and 235 mV for HER to achieve the current density of 10 mA cm−2, respectively. Meantime, L−AA−BP‐1 : 1 presents a great OER and HER performance in the group of L−AA−BP with different weight ratios, requiring an overpotential of 459.5 mV for OER and 224 mV for HER to achieve the current density of 10 mAcm−2, respectively. And two groups of the samples significantly enhance the OER and HER performance of few−layer BP nanosheets (550 mV and 431 mV). In addition, both the consecutive cyclic voltammetry and chronoamperometric measurements reveal the outstanding electrocatalytic stability of the samples.