Large Accessible Surface Area Research Articles

Ultrathin g-C3N4 nanosheet with hierarchical pores and desirable energy band for highly efficient H2O2 production

H2O2 production through photocatalysis has been considered as a sustainable technique. Here, we report ultrathin g-C3N4 nanosheets with hierarchical pores and desirable energy band for high-efficiency photocatalytic H2O2 production. The resultant catalyst showing an ultra-high H2O2 production rate of 1083 μmol g−1 h−1, which is about seven times higher than that of bulk g-C3N4 and represents one of the most active photocatalysts for H2O2 production. DFT calculation and experimental studies revealed that the suitable energy band structure achieved by a phosphorus doping in g-C3N4 leading to the efficient yielding two-electron reduction of O2 to form H2O2. Meanwhile, the particular morphology provided a large accessible surface area, multi-mass transport channels and short charge transfer distance. The synergy effect of desirable energy band and hierarchical porous nanosheets bring the excellent photocatalytic activity. In addition, the simple preparation procedure and the non-metal properties make it have great potential for the practical application.

Chemical vapor deposition design of graphene powders toward energy applications

Graphene, sp2-bonded carbon atoms being regularly packed into a two-dimensional (2D) honeycomb structure, has attracted wide attentions, owing to its excellent electrical (the carrier mobility ~105 cm2 V–1 s–1), mechanical (~1.1 TPa), optical (the transparency of single layer graphene is about 97.7%) and thermal (the thermal conductivity ~5000 W m–1 K–1) properties. These unique properties make it suitable for use in transparent conductivity electrodes, field-electric transistors, photodetectors, light-emitting diodes, energy storage materials and many other areas. In particular, in comparison with the conventional 2D graphene films, three-dimensional graphene powders have presented great potentials in energy related applications because of their controllable structures, high specific surface areas and excellent electrical conductivity. There are mainly two synthetic routes for preparing graphene powder materials with specific structures and morphologies. One route deals with the preparation of graphite oxide sheets, then throughout chemical reduction process to obtain reduced graphene oxide. Although this method enables the realization of mass production of graphene powders with a relatively low cost, the materials obtained show quite poor crystal quality with high defect density, thereby greatly limiting the fast electron transport in high-energy-density and high-power-density energy storage devices. The other route is the chemical vapor deposition (CVD) growth of graphene powders with/without template-direction. Taking advantage of the CVD method, the crystal quality and electrical conductivity properties of graphene powders can be obviously improved. Meanwhile, the templates used during growth process can effectively control the morphologies of graphene powders, realizing graphene materials with high specific surface areas. Moreover, by selecting proper carbon sources or other reaction precursors, graphene powders with heteroatomic (N, B, P, S) doping can be achieved. This route facilitates mass production of high-crystal quality graphene with specific architecture, controllable layer numbers and effective heteroatomic doping, thus greatly promoting the application of graphene-based energy related devices. Herein, this review highlights the recent advances in the chemical vapor deposition design of graphene materials and their related energy applications. Firstly, a brief introduction with respect to the CVD synthesis of graphene powders, including template-directed growth and template-free growth is provided. Taking use of metal particles, oxide powders, chloride particles and biomineral materials as the growth substrates (templates), graphene powders with circular, cubic or other specific morphologies have been successfully synthesized. The growth mechanisms of graphene on metal substrates and non-metal substrates are also probed. Upon summarizing the direct growth methods of graphene powders by CVD and the related growth mechanisms, energy applications pertaining to batteries (lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, potassium-ion batteries), supercapacitors, printed energy storage devices and catalysts are further highlighted. Because of the unique characteristics of high electrical conductivity, large accessible surface area, and excellent electrochemical properties, graphene-based materials exhibit high performances in energy-related applications. Finally, further development and challenges of the CVD graphene materials in this emerging field are proposed.

Tassel tree flowers-derived hierarchically porous carbons with high surface area for high-performance flexible all-solid-state symmetric supercapacitors

Abstract Waste biomass is a naturally abundant and sustainable resource, and however their unreasonable utilization could arouse some severe environmental issues and pollution. Thus, the efficient utilization and conversion of waste biomass are greatly essential in alleviating the burden on already-strained energy and environmental crisis. In this work, we reported a simple, one-step pyrolysis and activation strategy to prepare porous carbons for use as electrode materials of energy storage devices using waste biomass as carbon source. The obtained porous carbons not only exhibited a well-interconnected 3D honeycomb-like microstructure, but also owned a hierarchical porosity with abundant micropores and suitable proportion of mesopore, as well as nitrogen from the biomass being self-doped in the resultant carbon skeleton. The optimal material possessed a large accessible surface area of 3310 m2 g−1 and a high hierarchical porosity of 1.79 cm3 g−1. The obtained materials exhibited a remarkably electrochemical capacitive performance including a high rate capacity, and a high capacitance of 394 F g−1 at 0.5 A g−1 was delivered in 6 M KOH electrolyte. Importantly, the assembled symmetric flexible all-solid-state capacitor exhibited a high energy density of 18 Wh kg−1 and a power density of 246 W kg−1, as well as a good cycling stability of a 96 % capacitance retention after 5000 cycles in a PVA/KOH gel electrolyte. Our proposed strategy not only realized the large-scale utilization and conversion of waste biomass to ease environmental issues, but also achieved the possibility of the production of a high-performance supercapacitor electrode in industry, which was a sample to convert the waste biomass into a high-value-added product.

Integrated structural design of polyaniline-modified nitrogen-doped hierarchical porous carbon nanofibers as binder-free electrodes toward all-solid-state flexible supercapacitors

Electrode materials with rationally designed architecture are crucial to achieve high-performance supercapacitors. However, there is still a great challenge for integrating the features of large accessible surface areas, fast electron/ion transport kinetics and favorable mechanical flexibility within a single electrode. Herein, we propose a facile approach to fabricate high-performance freestanding carbon-based electrode of polyaniline modified nitrogen-doped hierarchical porous carbon nanofibers, which effectively combine the merits of highly conductive electrospun carbon nanofibers with hierarchical porous structure, suitable nitrogen content as well as pseudocapacitive materials. Benefiting from the well-designed architecture, the as-assembled symmetric all-solid-state flexible device exhibits a high specific capacitance of 260 F g−1 at 0.5 A g−1 and high rate capability with a capacitance retention of 60% at 16 A g−1. Furthermore, the device also displays a desirable energy density of 8.9 Wh kg−1 with power density of 0.27 kW kg−1 and excellent cycling stability with 80.1% capacitance retention after 10,000 charge-discharge cycles at 2 A g−1. Eventually, the as-designed composite electrodes open up new avenues for facile construction of high-performance supercapacitor electrodes.

Competitive Adsorption of Methanol-Acetone on Surface Functionalization (-COOH, -OH, -NH2, and -SO3H): Grand Canonical Monte Carlo and Density Functional Theory Simulations.

The capture and separation properties of surface-functionalized activated carbons (AC-Rs, R= -COOH, -OH, -NH2, and -SO3H) for the methanol-acetone mixture were investigated for the first time by grand canonical Monte Carlo simulation (GCMC)and density functional theory(DFT). The effects of surface functional groups and structural characteristics of AC-Rs on the adsorption and separation behaviors of methanol and acetone were clarified. The surface functional group with strong electron-donating or electron-accepting capacity (i.e., -NH2, -OH, and -SO3H) was a crucial factor for the methanol-acetone capture and separation performance at the lower pressure range, and the accessible surface area was found to be another determinative factor. AC-NH2 with the relatively large accessible surface area (4497 m2/g) exhibited an efficient capture performance for the single component (15.7 mol/kg for methanol and 6.7 mol/kg for acetone) and the highest methanol/acetone selectivity (∼23) at 0.02 kPa. At high pressures, the surface functionalization and available pore volume of AC-Rs played pivotal roles in the adsorptive separation process. This study provided mechanistic insights on how the surface functional groups affected the capture and separation properties of ACs, which would further provide a rational alternative strategy in the preparation and synthesis of ACs for the effective gas mixture separation.

Enhancing the CO2 separation performance of polymer membranes via the incorporation of amine-functionalized HKUST-1 nanocrystals

Abstract HKUST-1 nanocrystals with large accessible surface areas and high porosity were functionalized with amine groups and incorporated into polymer matrices to form mixed-matrix membranes for application in CO2 capture. This gas permeation study reveals that pristine HKUST-1 nanocrystals are able to increase the gas permeabilities of polymer membranes with no noticeable effect on CO2/N2 selectivity as a result of their high porosity and large pore dimensions. Contrarily, 20 wt% amine-functionalized HKUST-1 can improve the CO2/N2 selectivity of polymer membranes by as much as 38%. As shown in a detailed analysis of the diffusivity-solubility, the amine-functionalized HKUST-1 suppressed N2 solubility and diffusivity but enhanced CO2 diffusivity. This resulted in an increased CO2/N2 perm-selectivity. Meanwhile, the pristine HKUST-1 nanocrystals increased the diffusivity and solubility of both species in a non-selective manner. These results indicate the feasibility of tuning the CO2 separation performance of mixed-matrix membranes by introducing amine functionality into the filler.

Synthesis and characterization of Ni0.3Co2.7O4 oxide nanoparticles immobilized in Teflon cavity electrode for organic pollutants degradation

A simple cost effective sol-gel process for the nickel cobaltite oxide production using sulfate precursors and citric acid as chelating agent is reported. The obtained nanopowders were characterized, immobilized in teflon cavity electrode to investigate their catalytic properties, using ethylene glycol and methylene blue as contaminants models in various conditions. The electrode stability and re-utilization have also been discussed. Spinel Ni0.3Co2.7O4 nanocristallites of about 11 nm with regular cauliflower-like shape agglomeration and high surface area equals 49 m2.g−1 and having mesoporous structure, were obtained. This oxide displays two absorption transitions at 1.61 and 3.26 eV, besides; it can be stored for long-terms since its preparation. The formed electrode exhibits excellent electrochemical stability with sufficient charge transfer kinetics and a large accessible mesoporous surface area. Furthermore this electrode is powerful to remove both pollutants, by pseudo-first order mechanism, without significant adsorption and can be used again for several cycles. Indeed, it was found that the photoelectrocatalytic process is more efficient than photocatalytic or electrocatalytic oxidation alone, indicating the light synergistic effect combined with the applied potential. Low cost, simple preparation, long-term storage, operational stability and ability to degrade organics can make this electrode a candidate for industrial use.

Multifunctional core-shell-like nanoarchitectures for hybrid supercapacitors with high capacity and long-term cycling durability

Transition metal oxide/hydroxide with multifunctional hierarchical nanostructures has attracted widespread attention in supercapacitors (SCs) because of their large accessible surface area, high electrochemical activity and superior redox chemistry. Herein, core-shell-like copper (Cu) hydroxide nanotube arrays grafted nickel aluminum layered double hydroxide nanosheets were facilely synthesized on porous Cu foam (CH NTAs@NiAl LDH NSs) for use as an efficient battery-type electrode in hybrid SCs. With the synergistic effects of NiAl LDH NSs on well-adhered CH NTAs/CF, the core-shell-like composite (prepared for 24 h) delivered a maximum areal capacity of 334.3 μAh/cm2 at a current density of 3 mA/cm2 in 2 M KOH electrolyte, which is comparatively higher than other samples synthesized at different growth times. Moreover, the core-shell-like CH NTAs@NiAl LDH NSs-24 demonstrated an outstanding cycling stability of 134.3% after 10,000 cycles. Utilizing high capacity and stability of CH NTAs@NiAl LDH NSs-24, a pouch-type hybrid SC was further assembled with core-shell-like composite as a positive electrode and reduced graphene oxide as a negative electrode with a filter paper as a separator in aqueous alkaline electrolyte. The hybrid SC showed a high areal capacity of 250 μAh/cm2 at 2 mA/cm2 with maximum areal energy and power densities of 181.9 μWh/cm2 and 24,991.5 μW/cm2, respectively. Successfully harvesting the solar energy via solar cell panel and subsequently delivering the stored energy to switching and proximity applications also demonstrated the real-time applicability of our hybrid SCs.

Excavated and dendritic Pt-Co nanocubes as efficient ethylene glycol and glycerol oxidation electrocatalysts

Noble metal electrocatalysts with excavated and dendritic architectures have recently attracted growing attention for their large accessible surface areas and high density of under-coordinated atoms. However, it is a tough challenge to avoid the atoms migrating to the corners and kinks and finally obtain the excavated structure, after the complicated interaction among multiple factors during the synthesis process, let alone the growth control of dendritic shape. Herein we demonstrate a facile strategy to synthesize Pt-Co nanocubes having excavated and dendritic structure (Pt-Co EDNCs). Specifically, the Pt-Co EDNC nanocrystal is composed of a deeply excavated nanocube and nanodendrites selectively protruding on the vertexes. Further electrocatalytic investigations showed that Pt-Co EDNCs exhibited enhanced catalytic properties towards the electro-oxidation of ethylene glycol and glycerol compared with commercial Pt/C, which could be attributed to both its unique structure and the synergism between Pt and Co.

Polyaniline-modified renewable biocarbon composites as an efficient hybrid electrode for supercapacitors

Polyaniline-modified renewable biocarbon (ACPANI) composites were prepared via static low-temperature in situ polymerization of aniline monomers on the biomass-based porous biocarbon (AC) that was derived from watermelon rind. In the ACPANI composites, the AC biocarbon was served as a three-dimensional supporting skeleton for polyaniline (PANI) to provide a large accessible surface area, and PANI was used to improve their electrochemical performances. The porous AC biocarbon was coated with nanofibrous arrays of PANI via electrostatic interaction and van der Waals forces. The ACPANI-2 composite that obtained with an AC/aniline mass ratio of 20:80 exhibited an excellent electrochemical performance as a hybrid electrode for supercapacitor. A superb specific capacitance of 520 F g−1 for ACPANI-2 was achieved at a current density of 1 A g−1, and a high cycling stability with a retention rate of capacitance of 71.2% after 5000 cycles was confirmed. Furthermore, an asymmetric supercapacitor using ACPANI-2 as a positive electrode assembled with the AC negative electrode acquired a cell voltage of 1.4 V and a high energy density of 29.3 Wh kg−1. Therefore, the ACPANI composite is suggested to be a promising candidate for electrochemical supercapacitor.

Applications of 3D Potassium-Ion Pre-Intercalated Graphene for Perovskite and Dye-Sensitized Solar Cells

3D potassium-ion preintercalated graphene (KIPIG), which was recently invented via the reaction of potassium and CO, shows unique properties including large accessible surface area and excellent electrical conductivity for electrodes. Herein, it was revealed that the perovskite solar cells (PSC) and dye-sensitized solar cells (DSSC) with KIPIG electrode exhibited high power conversion efficiencies of 7.81% and 9.12%, respectively. This work not only proves that 3D KIPIG is an efficient electrode material, but also provides a strategy to reduce the fabrication cost of solar cells.

Nitrogen-rich microporous carbon materials for high-performance membrane capacitive deionization

Novel two-dimensional carbon nitride hexagonal-like sheets were fabricated from thermal condensation, which uses hexaazatriphenylene-based precursor prepared microporous and oxidation resistant carbons materials (HAT-CN). The results show that the as-prepared HAT-CN is the first electrode utilized in capacitive deionization, due to the rich heteroatom and border-group content, as well as the potential collaborative effect of C and N atoms, displaying the quick ion diffusion and strong charge transfer performance. Additionally, the capacitive deionization performance of HAT-CN is improved by the synergistic contribution of a large accessible surface area, large pore volume, and high graphitization. The electrode of HAT-CN was carbonized at 550 °C which display an excellent specific capacitance of 179.2 F g−1 in 1-M NaCl solution at a scan rate of 5 mV s−1. Subsequently, a high salt adsorption capacity of 24.66 mg g−1 was attained for an applied voltage of 1.2 V in 500 mg L−1 NaCl solution, showing good cyclic stability at 30 cycles. Considering those excellent properties of the prepared HAT-CN, the capacitive deionization electrode should be an ideal candidate for high-performance deionization application.

Densely integrated Co, N-Codoped Graphene@Carbon nanotube porous hybrids for high-performance lithium-sulfur batteries

Design and synthesis of multifunctional sulfur hosts with comprehensively addressed conductivity, porosity and polarity is vital but challenging in the development of high-performance lithium-sulfur batteries. In this work, densely integrated Co,N-codoped graphene@carbon nanotubes porous hybrids (Co,N-G@CNT) are prepared as high-efficiency sulfur hosts for lithium sulfur batteries via reductive pyrolysis of (Co,Zn)-bimetallic zeolitic imidazolate frameworks separated graphene oxide sheets. The obtained Co,N-G@CNT possesses 3D interconnected conductive network, large nanopore volume and high accessible surface area as well as enriched doping sites, which endow the carbon matrix multifaceted abilities for sulfur accommodation and electron/ion transfer as well as polysulfides immobilization. Due to the rational structure design of the host material, the Co,N-G@CNT/S composite exhibits high sulfur utilization (1398 mA h g−1 at 0.2C), excellent rate capability (611 mA h g−1 at 6 C) as well as remarkable cycling stability (retained 659 mA h g−1 at 1C after 1500 cycles). This work provides a new perspective to function-directed structure design of sulfur hosts for lithium-sulfur batteries, and also holds great promise for the application in other energy storage/conversion systems such as metal air batteries, supercapacitors, and electrochemical catalysts.

Multicomponent Hierarchical Cu‐Doped NiCo‐LDH/CuO Double Arrays for Ultralong‐Life Hybrid Fiber Supercapacitor

AbstractFiber supercapacitors have aroused great interest in the field of portable and wearable electronic devices. However, the restrained surface area of fibers and limited reaction kinetics of active materials are unfavorable for performance enhancement. Herein, an efficient multicomponent hierarchical structure is constructed by integrating the Cu‐doped cobalt copper carbonate hydroxide@nickel cobalt layered double hydroxide (CCCH@NiCo‐LDH) core–shell nanowire arrays (NWAs) on Cu fibers with highly conductive Au‐modified CuO nanosheets (CCCH@NiCo‐LDH NWAs@Au–CuO/Cu) via a novel in situ corrosion growth method. This multicomponent hierarchical structure contributes to a large accessible surface area, which results in sufficient permeation of the electrolyte. The Cu dopant could reduce the work function and facilitate fast charge transfer kinetics. Therefore, the effective ion diffusion and electron conduction will facilitate the electrochemical reaction kinetics of the electrode. Benefiting from this unique structure, the electrode delivers a high specific capacitance (1.97 F cm−2/1237 F g−1/193.3 mAh g−1) and cycling stability (90.8% after 30 000 cycles), exhibiting superb performance compared with most oxide‐based fiber electrodes. Furthermore, the hybrid fiber supercapacitor of CCCH@NiCo‐LDH NWAs@Au–CuO/Cu//VN/carbon fibers is fabricated, providing a remarkable maximal energy density of 34.97 Wh kg−1 and a power density of 13.86 kW kg−1, exhibiting a great potential in high‐performance fiber‐shape energy‐related systems.

Different morphologies of Ni(OH)2 derived from a MOF template for high performance supercapacitors

Owing to the limited electrochemical performance of pristine metal–organic frameworks (MOFs) for supercapacitors, precursor conversion method is employed to synthesize sheet-like and sphere-like Ni(OH)2 using a MOF template based on the exploration of Ni-MOF at different growth time. The morphology has significant impact on the electrochemical performance of Ni(OH)2 electrode, we compare the electrochemical behavior of sheet-like Ni(OH)2 and sphere-like Ni(OH)2 by means of CV, GCD and EIS test. Electrochemical evolution demonstrates that the sphere-like Ni(OH)2 delivers a superior specific capacitance (982 Fg−1 at 1 Ag−1), better cycling life span and also relatively low resistance, which can be attributed to its porous structure and large accessible specific surface area. Our findings lead us to conclude that the sphere-like Ni(OH)2 synthesized by a facile method is shown to be potentially attractive candidate in supercapacitors.

Adenovirus 5 recovery using nanofiber ion-exchange adsorbents.

Viral vectors such as adenovirus have successful applications in vaccines and gene therapy but the manufacture of the high-quality virus remains a challenge. It is desirable to use the adsorption-based chromatographic separations that so effectively underpin the therapeutic protein manufacture. However fundamental differences in the size and stability of this class of product mean it is necessary to revisit the design of sorbent's morphology and surface chemistry. In this study, the behaviour of a cellulose nanofiber ion-exchange sorbent derivatised with quaternary amine ligands at defined densities is characterised to address this. This material was selected as it has a large accessible surface area for viral particles and rapid process times. Initially, the impact of surface chemistry on infective product recovery using low (440 µmol/g), medium (750 µmol/g), and high (1029 µmol/g) ligand densities is studied. At higher densities product stability is reduced, this effect increased with prolonged adsorption durations of 24 min with just ~10% loss at low ligand density versus ~50% at high. This could be mitigated by using a high flow rate to reduce the cycle time to ~1 min. Next, the impact of ligand density on the separation's resolution was evaluated. Key to understanding virus quality is the virus particle: infectious virus particle ratio. It was found this parameter could be manipulated using ligand density and elution strategy. Together this provides a basis for viral vector separations that allows for their typically low titres and labile nature by using high liquid velocity to minimise both load and on-column times while separating key product and process-related impurities.

A novel sensitive and selective electrochemical sensor based on integration of molecularly imprinted with hollow silver nanospheres for determination of carbamazepine

An electrochemical sensor based on hollow silver nanospheres (hAgNS) and molecularly imprinted polymer (MIP) was developed for drug analysis by using carbamazepine (CBZ) as a model analyte. hAgNS, serving as a support material for MIP immobilization, possesses large accessible surface area with superb electric conductivity, while electrochemically synthesized MIP film warrants improved selectivity for CBZ. Quantification based on the “MIP/gate effect” was performed by employing Fe(CN)63−/4− as the probe to indicate the current intensity. The sensor materials were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, a linear relationship of the electrical signal versus the concentration of CBZ was obtained in the range from 8.0 × 10−11 to 6.0 × 10−8 M with a detection limit of 3.2 × 10−11 M (S/N = 3). Moreover, the prepared sensor exhibited specific detection of CBZ over its structural analogues and interferents, and the established electrochemical method was validated using the standard method-high performance liquid chromatography (HPLC). Eventually, rapid and accurate determination of CBZ in rat serum and cell samples was carried out after easy sample pretreatment.

Three-dimensional Ni/MnO2 nanocylinder array with high capacitance for supercapacitors

Abstract Though high-capacitance transition metal oxides are considered as promising pseudocapacitive materials to achieve high-energy storage for supercapacitors, the practical capacitance is far from the theoretical values because of their intrinsic poor abilities about the electronic and ionic transports. Here, to tackle these problems, we develop a hybrid nanostructured electrode in a facile process, in which layer-structured δ-MnO2 nanosheets are anchored onto seamless three-dimensional Ni nanocylinder arrays. The resultant Ni/δ-MnO2 nanocylinder arrays exhibit high specific capacitance up to 883.2 Fg−1 at a scan rate of 10 mVs−1 and achieve high energy density about 108 Whkg−1 at a power of 2.4 kWkg−1. The improved electrochemical performance mainly benefits from the vertically aligned Ni/δ-MnO2 hybrid structure. Owing to such a hybrid structure the ion/electron transports are facilitated along the nanocylinders due to the reduction in the transport distance, and large accessible surface area is also provided for anchoring more high-capacitance materials. Moreover, the additional contact resistance can be dramatically reduced owing to the large interplanar spacing of δ-MnO2 and ordered semicoherent interface of Ni/δ-MnO2.

Facile Preparation of 2D Nitrogen and Sulfur Co-Doped Porous Carbon Nanosheets for High-Performance Supercapacitors

2D nitrogen and sulfur co-doped porous carbon nanosheets (NSPCSs) are facilely prepared from methyl orange (MO) doped 1D polypyrrole (PPy) nanotubes by an one-step heat-treating process in the presence of KOH under nitrogen atmosphere. The combination of the dedoping owing to the interreaction between MO and KOH, the pyrolysis of PPy, and the activation by KOH at high temperature results in the damage and exfoliation of PPy nanotube, and finally forms 2D NSPCSs. As-prepared NSPCSs possess high surface area, large pore volume, and hierarchical porosity. This unique architecture constructs interconnected electrolyte-transport channels, shortens the ion-diffusion path, and provides large accessible surface area. In addition, co-doping of nitrogen and sulfur not only enhances the wettability of carbon materials but also provides pseudocapacitance. As a result, the specific capacitance of NSPCNSs can reach up to 300.8 F g−1. Furthermore, NSPCSs display good rate capability (192.9 F g−1 remained at 20 A g−1) and excellent cycling stability (97.5% retention over 10000 cycles). The assembled two-electrode device delivers an energy density of 8.19 Wh kg−1 at a power density of 0.3 kW kg−1.

Direct Electrodeposition to Fabricate 3D Graphene Network Modified Glassy Carbon Electrode for Sensitive Determination of Tadalafil

In this work, pulse potential method (PPM) was presented to fabricate directly three-dimensional graphene (3DG) network on the surface of glassy carbon electrode (GCE). The morphological characteristic of 3DG network were investigated by means of Raman spectra, scanning electron microscopy (SEM) and electrochemical experiments. The 3DG network as a new voltammetric material was used to develop a high-sensitive electrochemical sensor for determination of tadalafil. Electrochemical tests showed that the 3DG network can help to enhance response due to the large accessible surface area as well as its excellent conductivity. Under the optimum conditions, the electrochemical response showed a linear relationship with tadalafil concentrations in the range of [Formula: see text]–[Formula: see text][Formula: see text]mol[Formula: see text]L[Formula: see text], and a low detection limit of [Formula: see text][Formula: see text]mol[Formula: see text]L[Formula: see text] was achieved for tadalafil. Moreover, the fabricated electrochemical sensor exhibited excellent selectivity, stability, reproducibility and repeatability, which make it very suitable for analytical applications for the trace level determination of tadalafil.