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N-doped carbon-based single-atom catalysts (NC-SACs) are widely researched in various electrochemical reactions due to high metal atom utilization and catalytic activity. The catalytic activity of NC-SACs originates from the coordinating structure between single metal site (M) and the doped nitrogen (N) in carbon matrix by forming M-Nx-C structure (1≤ x≤ 4). The M-N4-C structure is widely considered to be the most stable and effective catalytic site. However, there is no in-depth research for the “x” modulation in Pt-Nx-C structure and the corresponding catalytic properties. Herein, atomically dispersed Pt on N-doped carbon (Pt-NC) with Pt-Nx-C structure (1≤ x≤ 4), as a research model, is fabricated by a ZIF-8 template and applied to catalytic oxygen reduction. Different carbonization temperatures are used to control N loss, and then modulate the N coordination of Pt-Nx-C structure. The Pt-NC has the predictable low half-wave potential (E1/2) of 0.72 V vs RHE compared to the Pt/C 20% of 0.81V due to low Pt content. Remarkably, the Pt-NC shows a high onset potential (1.10 V vs RHE, determined for j = -0.1 mA cm2) and a high current density of 5.2 mA cm−2, more positive and higher than that of Pt/C 20% (0.96 V) and 4.9 mA cm−2, respectively. As the structural characterization and DFT simulation confirmed, the reducing Pt-N coordination number induces low valence of Pt atoms and low free energy of oxygen reduction, which is responsible for the improved catalytic activity. Furthermore, the Pt-NC shows high mass activity (172 times higher than that of Pt/C 20%), better stability and methanol crossover resistance.

Heteroatom co-doping has been considered as an effective strategy to simultaneously overcome intrinsic shortcomings of g-C3N4 to achieve enhanced photocatalytic properties, in which the involved dopants could play its role in altering electronic structure, optical absorption and charge separation of the catalyst. Herein, W/O co-doped hollow g-C3N4 tubular structures are successfully obtained for the first time via a one-step thermal decomposition. By W/O co-doping, architecture of g-C3N4 is able to be modulated with enhanced optical absorption towards visible region. In addition, narrowed band gap and restrained charge recombination are conducive for the excitation of electron-hole pairs and transportation. Photocatalytic water splitting tests indicate that the co-doped hollow tubular g-C3N4 structures enable superior activity for generating hydrogen up to 403.57 μmol g−1 h−1 driven by visible light, nearly 2.5 times as high as that of pristine g-C3N4. This work presents a rational strategy to design co-doped g-C3N4 as an efficient visible-light-driven photocatalyst.

Three-dimensional (3D) hierarchical Pt/TiO2@C core-shell nanowire networks with high surface area have been constructed via wet chemical approaches. The 3D TiO2 nanowire framework was in situ synthesized within a porous titanium foam by hydrothermal method followed by carbon coating and self-assembled growth of ultrathin Pt nanowires. Structural characterization indicates that single crystalline ultrathin Pt nanowires of 3–5 nm in diameter were vertically distributed on the anatase TiO2 nanowires covered with a 2–4 nm thin carbon layer. The 3D hierarchical Pt/TiO2@C nanostructure demonstrates evidently higher catalytic activities towards methanol oxidation than the commercial Pt/C catalyst. The catalytic current density of the hierarchical catalyst is 1.6 times as high as that of the commercial Pt/C, and the oxidation onset potential (0.35 V vs. Ag/AgCl) is more negative than the commercial one (0.46 V vs. Ag/AgCl). Synergistic effect between the ultrathin Pt nanowires and the TiO2@C core-shell nanostructure accounts for the enhanced catalytic properties, which can be determined by X-ray photoelectron spectroscopy (XPS) investigation. The obtained hierarchical Pt/TiO2@C nanowire networks promise great potential in producing anode catalysts for direct methanol fuel cells applications.

Efficient exfoliation of layered materials has attracted considerable attention in various applications due to their superior photoelectric, physical and chemical properties. Here, we report a universal, rapid approach to prepare the two-dimensional (2D) nanosheets and zero-dimensional (0D) quantum dots (QDs) using a simple cryo-mediation liquid phase exfoliation of layered materials (graphite, MoS2, WS2). The QDs decorated nanosheets 0D/2D homostructure can be subsequently formed by the self-assembly of the as-exfoliated QDs and nanosheets. The unique structural properties of the mono- or few-layer mesoporous nanosheets interspersed with QDs can expose abundant active edge sites as well as improve the conductivity, which exhibits excellent activity and stability towards electrocatalytic hydrogen evolution reaction (HER). This work offers a powerful methodology to prepare 2D homostructures from a variety of layered materials.

Atomically thin 2D materials with high surface areas allow engineering its physical and chemical properties with help of combining or decorating with different classes of materials. The hybrid or heterostructure of two different atomically thin materials exhibits completely different chemical and electronics behavior as compared to its parent components. Here, MoS2 quantum dots (QDs) are decorated onto ultrathin NiO nanosheets (NSs) by using a one-pot hydrothermal process. Uniformly dispersed MoS2 QDs and ultrathin NiO NSs hybrid/heterostructure can provide more active reaction sites and accelerate the charge transfer rate. Benefiting from the heterointerfaces synergistic effect between MoS2 QDs and NiO NSs, the MoS2 QDs/NiO NSs electrode exhibits excellent electrocatalytic activity towards both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a bifunctional electrocatalyst, the MoS2 QDs/NiO NSs electrode has achieved highly efficient overall water splitting activity, which needs a low voltage of 1.61 V to deliver a 10 mA cm−2 with superior stability.

A carbon microtube aerogel (CMA) with hydrophobicity, strong adsorption capacity, and superb recyclability was obtained by a feasible approach with economical raw material, such as kapok fiber. The CMA possesses a great adsorption capacity of 78-348 times its weight. Attributed to its outstanding thermal stability and excellent mechanical properties, the CMA can be used for many cycles of distillation, squeezing, and combustion without degradation, which suggests a potential practical application in oil-water separation. In addition, the adsorption capacity still retained 98% by distillation, 97% by squeezing, and 90% by combustion after 10 cycles. Therefore, the obtained CMA has a broad prospect as an economical, efficient, and environmentally friendly adsorbent. National Research Foundation (NRF) This work was financially supported by Singapore National Research Foundation under NRF RF Award No. MOE2016- T2-1-131, Tier 1 2017-T1-001-075.

Three-dimensional (3D) carbon-coated NiCo2S4 nanowires structures doped with nitrogen are used for energy storage and conversions. The nitrogen doping in both the carbon layer and NiCo2S4 nanowires enhances the electrochemical performances. Here, an easily scalable and simple temperature treatment has been used to decorate carbon-coated NiCo2S4 nanowires with nitrogen doping (NC@NiCo2S4 NWs) in 3D carbon architecture (carbon cloth). Benefiting from the nitrogen doping and ultrathin carbon layer, the as-prepared 3D NC@NiCo2S4 NWs electrode exhibits the superior electrochemical performance for both asymmetric supercapacitor and electrocatalytic water splitting. An asymmetric supercapacitor assembled by the NC@NiCo2S4 NWs and active carbon electrodes achieves a high energy density of 1.72?mWh?cm?3 (68.87?Wh?kg?1) under a power density of 10.63?mW?cm?3 (425?W?kg?1) with 90.1% retention of initial capacitance after 10,000 cycles. When employed as the electrocatalyst, the NC@NiCo2S4 NWs show high activities towards electrocatalytic water splitting., by Chandra Sekhar Tiwary et al.

As CO2 emissions are sharply increasing, processes for converting CO2 into value-added products are becoming more desirable. Ruthenium-based catalysts are the most active for CO2 methanation; howev...

As a typical wide bandgap semiconductor material, silicon carbide (SiC) has been widely used in the field of electrical and electronic materials due to its excellent electron transport characteristics. In this paper, two-dimensional (2D) ultrathin SiC nanosheets (SiC NSs) were for the first time achieved directly through an improved cryo-mediated liquid phase exfoliation process. Then three-dimensional (3D) SiC/rGO hybrid aerogels were assembled by a facile hydrothermal treatment followed by freeze drying. The supercapacitive performance of the as-obtained 3D SiC/rGO hybrid aerogels is systematically investigated by the combined use of cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The specific energy of 53.22 Wh kg−1 at a current density of 1 A g−1 could be achieved with outstanding long-term cycling stability, demonstrating that ultrathin SiC NSs may be developed as promising electrode materials for high performance supercapacitors.

Nitrogen-doped hierarchical porous carbon with a high-specific surface area has been successfully synthesized via a one-step template carbonization-activation of nicotinic acid. The mass ratio of Mg (OH)2 and KOH to carbon precursor plays a crucial role in controlling porosity and nitrogen content of the product. Our optimized sample shows a hierarchical porous structure with a high surface area (2608 m2 g−1), large pore volume (4.0 cm3 g−1), and reasonable incorporation of nitrogen (2.2%). In addition, the electrode made using this optimized material shows a maximum specific capacitance of 282 F g−1 at a current density of 1 A g−1 and outstanding rate performance (64% capacitance retention at 20 A g−1). An assembled symmetric capacitor using this material displays a maximum energy density of 21.5 Wh kg−1 and 95% retention over 5000 cycles at 5 A g−1 at 25 °C. Moreover, our facile, simple, and efficient method of fabrication paves the way large-scale application of these porous carbon materials for high-performance supercapacitors.

In this work, we report a facile cryo-mediated liquid phase exfoliation method to synthesize water-soluble defect-rich MoS2 ultrathin nanosheets (d-MoS2 NSs) with the assistance of NaBH4 in the sol...

Highly sensitive analysis of cancer biomarkers demonstrates an important impact in early diagnosis and therapies of cancer. A novel surface-enhanced Raman scattering (SERS) based immunoassay using microfluidic technique was reported for rapid analysis of prostate-specific antigen (PSA) biomarker. It is a useful screening test to discriminate prostate cancer and other diseases related to prostate. A "sandwich" immunoassay based on SERS nanotags, PSA biomarkers, and magnetic beads was applied on a pump-free microfluidic sensor. Magnetic immunocomplexes are isolated and trapped at the detection chamber by a permanent magnet integrated into the chip. The PBS buffer washed magnetic immunocomplexes and brought the free gold nanoparticles to the downsteam channel for waste. Our results show a good linear response in the range from 0.01 to 100 ng mL-1. The limit of detection of the PSA level is estimated to be below 0.01 ng mL-1 using this chip. This detection level of PSA biomarker in human serum can be accomplished in 5 min without manual incubation and a heavy syringe pump. To the best of our knowledge, this is the first SERS-based immunoassay which applied a pump-free microfluidic chip as a detection platform. We believe that the proposed method reveals a valuable potential tool for the diagnosis of prostate cancer.

Here we present direct exfoliation of ultrathin silicon nanosheets from commercial silicon powders through an improved liquid phase exfoliation procedure. The feasibility of exfoliation was ascribed to the intrinsic anisotropic lattice structure, which allowed the oriented propagations of cryo-mediation-induced quenching cracks with the assistance of sonication. It was also revealed that the solid-solvent interface played a critical role in determining the morphology of exfoliated pieces as well as the exfoliation efficiency. Moreover, due to its superior morphology, enlarged surface area, and improved photon absorption, the resulting ultrathin silicon nanosheets presented enhanced and visible light responsive photocatalytic hydrogen generation performance, even without applying any co-catalyst.

Designed growth of tungsten oxide (WO3)/poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell hybrid nanorod arrays has been obtained by combining solvothermal and in situ electropolymerization techniques. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and Raman characterization results indicate that the hybrid nanorods are composed of single crystalline WO3 nanocores wrapped by thin amorphous PEDOT nanoshells. The hybrid nanorods exhibit promising electrochromic performance of much shorter response time (3.8 s for coloring and 3.6 s for bleaching) than the bare WO3 nanorods (12.4 s for coloring and 7.6 s for bleaching), while the optical contrast of the hybrid nanorods increases from 26% of PEDOT to 72% in 633 nm. And the coloring efficiency and stability of the core/shell hybrid nanorods are also enhanced compared to the individual components. Dynamic analysis suggests a synergistic effect between the WO3 nanocore and the PEDOT nanoshell. In addition, color depth and optical contrast of the hybrid nanorods can be modulated by adjusting the applied voltage and the deposition of the PEDOT nanoshell. The hybrid nanorod films obtained by the cost-effective wet chemical methods may find promising applications in energy-saving windows, smart displays as well as other energy efficient technologies.

Unlike inorganic crystals, metal-organic frameworks do not have a well-developed nanostructure library, and establishing their appropriately diverse and complex architectures remains a major challenge. Here, we demonstrate a general route to control metal-organic framework structure by a solvent-assisted ligand exchange approach. Thirteen different types of metal-organic framework structures have been prepared successfully. To demonstrate a proof of concept application, we used the obtained metal-organic framework materials as precursors for synthesizing nanoporous carbons and investigated their electrochemical Na+ storage properties. Due to the unique architecture, the one-dimensional nanoporous carbon derived from double-shelled ZnCo bimetallic zeolitic imidazolate framework nanotubes exhibits high specific capacity as well as superior rate capability and cycling stability. Our study offers an avenue for the controllable preparation of well-designed meta-organic framework structures and their derivatives, which would further broaden the application opportunities of metal-organic framework materials., Metal-organic frameworks are promising for a range of applications, but architectural control is challenging. Here the authors use solvent-assisted ligand exchange to access a variety of metal-organic framework nanomaterials for precursors of nanoporous carbon with sodium ion storage properties.

Substrate materials play a significant role in the improvement of electrochemical biosensors. In the present work, NiO nanoflake arrays were fully and uniformly decorated with Mn3O4 nanoparticles by stepwise method. The as-prepared samples were characterized by scanning electron microscopy (SEM), x-ray diffractionmeter (XRD), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDS), and chronoamperometry. Subsequently, the optimized Mn3O4 nanoparticle/NiO nanoflake arrays were employed as substrate to fabricate electrochemical biosensors for glucose determination. The results demonstrated that as-prepared glucose biosensors could achieve 226.2 μA mM−1 cm−2 of sensitivity and 1.0 μM of detection limit, respectively. In addition, the linear range was between 9.9 and 3665.0 μM. The developed substrate could also be extended to construct electrochemical biosensors based on other oxidase with excellent performance.

High-performance noble metal-free electrocatalysts are extremely desired for overall water splitting, but there are huge challenges. Herein, we report a novel one-step electrochemical anodic oxidation and cathodic deposition strategy to in situ fabricate three-dimensional coral-like Ni3S2 on Ni foam (NF) for electrocatalytic overall water splitting. In a typical two-electrode cell, NF acts as both cathodic and anodic electrodes with thiourea aqueous solution as the electrolyte. The nickel ions from the anodic oxidation of NF are directly used as nickel sources to form 3D coral-like Ni3S2/NF by the cathodic deposition method simultaneously. The optimal 3D Ni3S2/NF-4 electrode shows high electrocatalytic activity for hydrogen evolution reaction and oxygen evolution reaction with low overpotentials of 89 and 242 mV, respectively, to afford 10 mA cm–2. When the as-obtained Ni3S2/NF-4 is used as a bifunctional electrocatalyst in an electrolyzer, a low applied voltage of 1.577 V is needed to reach 10 mA cm–2, w...

A novel tube-in-tube nanostructure of MnO2@ TiO2 hybrid arrays has been obtained by a facile and controllable chemical bath deposition method. Scrutiny on the hybrid arrays indicates that the chemical bath deposition method favors the growth of the MnO2 nanotubes with different diameter which can modulate the oxygen evolution reaction (OER) activity as well as bandgap width of the hybrid. In terms of OER activity, onset potential (Es) shifts negatively from 0.698 V (vs.Ag/AgCl) of pristine titania nanotube arrays (TNAs) to 0.501 V of the hybrid loaded with 26.6%wt MnO2, and the current density on the hybrid electrode can be significantly enhanced up to 20.87 mA/cm2, almost 97 times higher than that on TNAs electrode (0.214 mA/cm2). Optical absorption measurement suggests that the bandgap width (Eg) can be tuned by loading MnO2 onto the TNAs implying interaction between the MnO2 and TNAs. The MnO2@TiO2 hybrid nanotube arrays may find promising potential in electrochemical water splitting, photocatalysis, thermocatalysis and other sustainable energy applications.

The electrocatalytic hydrogen evolution reaction (HER) performance of carbon-coated β-NiS (NiS@C) nanocrystals has been investigated for the first time. The NiS@C nanocrystals were synthesized via a facile solvothermal method followed by in-situ carbonization process with the solvent (ethylene glycol) as the carbon source. Benefited from the well-dispersed NiS nanocrystals and the formation of carbon layer on NiS nanocrystals, the NiS@C nanocrystals displayed a high HER activity in 0.5 M H2SO4, which needed an overpotential of 85 mV to achieve current density of 10 mA cm−1 with a Tafel slope of 46 mV dec−1, as well as long term stability for HER. Additionally, the NiS@C nanocrystals also showed efficient electrocatalytic activity under alkaline media.

Self-supported CuO/Cu2O@CuO/Cu2O core–shell nanowire arrays (NWAs) are successfully fabricated by a simple and efficient method in this paper. Anodized Cu(OH)2 NWAs could in-situ convert to HKUST-1 at room temperature easily. Cu(OH)2 NWAs cores and HKUST-1 shells transform into CuO/Cu2O simultaneously after calcinations and form CuO/Cu2O@CuO/Cu2O core–shell NWAs. This smart configuration of the core–shell structure not only avoids the agglomeration of the traditional MOF-derived materials in particle-shape, but also facilitates the ion diffusion and increases the active sites. This novel structure is employed as substrate to construct nonenzymatic glucose sensors. The results indicate that glucose sensor based on CuO/Cu2O@CuO/Cu2O core–shell NWAs presents ultrahigh sensitivity (10,090 μA mM−1 cm−2), low detection limit (0.48 μM) and wide linear range (0.99–1,330 μM). In addition, it also shows excellent anti-interference ability toward uric acid, ascorbic acid and L-Cysteine co-existing with glucose, good reproducibility and superior ability of real sample analysis.

Novel NiCo2O4 nanoarrays have been in-situ grown on a La0.8Sr0.2MnO3-δ(LSM) cathode through a hydrothermal method, which presents the enhanced electrochemical performances of the LSM cathode for the intermediate temperature solid oxide fuel cells. XRD and SEM have been used to characterize phase structure and morphology of NiCo2O4 nanoarrays. The LSM cathode, modified by the NiCo2O4 nanoarrays, exhibits excellent electrochemical performances compared with the bare LSM cathode. The maximum peak power density of single cell, based on the NiCo2O4 nanoarrays modified the LSM cathode, reaches 957 mW cm−2 at 800 °C, which is almost two times higher than that for the cell based on the bare LSM cathode.

A novel and unique nickel-cobalt hydroxyfluorides (NiCo-HF) nanowires material is fabricated by one-pot solvothermal synthesis method for asymmetric supercapacitor. The synthesis mechanism and factors that influence the formation of the NiCo-HF nanowires have been further discussed. The as-prepared NiCo-HF electrode exhibits a high specific capacitance of 3,372.6 F g−1, and the capacitance retention of 94.3% can be achieved at a high current density of 20 A g−1 after 10,000 cycles. The outstanding electrochemical performance of the electrode can be attributed to the synergistic effect of the nanowires morphology and complicated redox process of active material. Furthermore, an asymmetric supercapacitor assembled with NiCo-HF nanowires as positive electrode and activated carbon as the negative electrode shows an ultrahigh energy density of 83.6 Wh kg−1 at a power density of 379.4 W kg−1 and an excellent cycling stability with 86.3% capacitance retention after 10,000 cycles, indicating that this novel material has great promise for potential application in energy storage device.

We first report that photoelectrochemical (PEC) performance of electrochemically hydrogenated TiO2 nanotube arrays (TNTAs) as high-efficiency photoanodes for solar water splitting could be well tuned by designing and adjusting the phase structure and composition of TNTAs. Among various TNTAs annealed at different temperature ranging from 300 to 700 °C, well-crystallized single anatase (A) phase TNTAs-400 photoanode shows the best photoresponse properties and PEC performance due to the favorable crystallinity, grain size and tubular structures. After electrochemical hydrogenation (EH), anatase-rutile (A-R) mixed phase EH-TNTAs-600 photoanode exhibits the highest photoactivity and PEC performance for solar water splitting. Under simulated solar illumination, EH-TNTAs-600 achieves the best photoconversion efficiency of up to 1.52% and maximum H2 generation rate of 40.4 µmol h−1 cm−2, outstripping other EH-TNTAs photoanodes. Systematic studies reveal that the signigicantly enhanced PEC performance for A-R mixed phaes EH-TNTAs-600 photoanode could be attributed to the synergy of A-R mixed phases and intentionally introduced Ti3+ (oxygen vacancies) which enhances the photoactivity over both UV and visible-light regions, and boosts both charge separation and transfer efficiencies. These findings provide new insight and guidelines for the construction of highly efficient TiO2-based devices for the application of solar water splitting.

The exploration of substrate materials to construct electrochemical biosensors for glucose monitoring in the field of clinical diagnosis, especially for diabetes is still being investigated extensively. In this paper, NiO/Fe2O3 nanocomposites are designed and synthesized by two-step hydrothermal approach in combination with calcinations. The morphology and microstructure are studied by SEM, XRD, XPS, and TEM systematically. Optimized NiO/Fe2O3 nanocomposites are employed as substrate to construct glucose biosensors, and the electrochemical properties are carried out by cyclic voltammetric and chronoamperometric techniques. The results indicate as-prepared biosensors achieve a high sensitivity of 230.5 μA cm−2 mM−1, wide linear range between 50 and 2867 μM, and low detection limit of 3.9 μM towards glucose detection. The synergistic effect between NiO and Fe2O3 as substrate to construct glucose biosensors is elucidated. The selectivity is acceptable based on the detection of glucose concentration for diabetics.

Developing suitable substrate materials is of significance in constructing electrochemical biosensors for fast and reliable quantification of molecules of chemical and biomedical interest. For practical applications, biosensors working at low negative potentials have the advantage of high selectivity and sensitivity. In this work, CeO2−x/C/rGO nanocomposites have been synthesized through the pyrolysis of metal organic frameworks with graphene oxide. The CeO2−x/C/rGO nanocomposites exhibit excellent catalytic properties towards H2O2, which is one of the uricase catalyzed intermediates at low working potentials due to the coexistence of Ce3+ and reduced graphene oxide (rGO). A novel biosensor based on the CeO2−x/C/rGO nanocomposites has been developed and utilized for the detection of uric acid, an important molecule in the biological and medical fields. The biosensor based on the CeO2−x/C/rGO nanocomposites presents a high sensitivity of 284.5 μA cm−2 mM−1 at −0.4 V (vs. SCE), a wide linear range between 49.8 and 1050.0 μM and a low detection limit of 2.0 μM. Moreover, it is found that the amperometric responses are free from interference of ascorbic acid and urea, which shows a great potential for practical applications.

Metal–organic framework-derived materials have attracted much attention due to their great potential for applications in energy storage and conversion. Herein, we report a rational design and organic solvent-free synthesis of MOF-74 and derived hybrid metal oxide nanowires with hollow structure. The evolution process and mechanism of MOF-74 have been investigated by adjusting solvent compositions and Ni/Co ratios. Different phases of metal oxide nanowires can be tailored after calcinations, enabling the systematic investigation of the effect of different metal species counts on the electrochemical properties of hybrid metal oxide nanomaterials. Results indicate that the hybrid metal oxides exhibit obvious advantages compared with monometallic oxides of Co3O4 and NiO, and NiO/NiCo2O4 (1 : 1) with two mixed phases of NiCo2O4 and NiO exhibits a superior specific capacity of 732.0C g−1 at a current density of 1 A g−1 among three different hybrid metal oxides. Furthermore, an assembled asymmetric supercapacitor device achieves a high specific energy density of 46.9 W h kg−1 at a specific power density of 425.3 W kg−1 with excellent cycling performance. The as-prepared materials will be competitive and promising candidates for electrochemical energy storage and other applications.

An organic–inorganic coaxial-structured hybrid of PPy/EH-TNTAs electrode with outstanding supercapacitive performance was developed by incorporating electroactive polypyrrole (PPy) into a highly-conductive TiO2 substrate, namely, electrochemically hydrogenated TiO2 nanotube arrays (EH-TNTAs) through a photo-assisted potentiodynamic electrodeposition route. The as-fabricated PPy/EH-TNTAs hybrid electrode achieves a specific capacitance of up to 614.7 F g−1 at 1.0 A g−1 with 87.4% of the initial capacitance remaining after 5000 cycles at 10 A g−1, outperforming other fabricated PPy-TNTAs hybrid electrodes. The photoelectrodeposited and electrodeposited hybrid samples as well as the EH-TNTAs-based and air–TNTAs-based hybrid samples were fully compared from electropolymerization process, morphology, structural feature and electrochemical perspectives. The results indicate that the synergy of remarkably improved conductivity and electrochemical properties of the TiO2 substrate induced by intentionally introduced Ti3+ (O-vacancies) as well as the homogenous and integrated deposition of PPy triggered by light illumination enabled the outstanding supercapacitive performance of the PPy/EH-TNTAs hybrid electrode. A symmetric supercapacitor device was assembled using the PPy/EH-TNTAs hybrid as both a positive and negative electrode, respectively. It displays a high energy density of 17.7 W h kg−1 at a power density of 1257 W kg−1. This organic–inorganic coaxial-structured PPy/EH-TNTAs electrode will be a competitive and promising candidate for application in future energy storage devices.

WO3 nanorod/V2O5 dot hybrid arrays have been successfully prepared by combining solvothermal and electrodeposition methods. Microstructural characterization evidences single crystallinity of WO3 nanorods decorated with V2O5 dots below 3 nm in average diameter. Electrochemical and electrochromic measurements reveal that the nanorod arrays demonstrate high transmittance modulation (57% at 776 nm), fast switching speeds (bleaching: 4.4 s and coloration: 4.8 s), multi-colors (black, green-yellow and orange-yellow) and high coloration efficiency (87.1 cm2 C−1 at 776 nm), which exhibited significantly improved electrochromic properties with superior cyclic stability compared to the individual components. Mechanistic investigation suggests that the synergistic effect between the V2O5 dots and the WO3 nanorods as well as the architecture of the aligned nanoarrays can promote the reaction dynamics and enhance the cyclic stability during the electrochromic process. The exceptional electrochromic properties of the WO3 nanorod/V2O5 dot arrays show their great potential in constructing high performance inorganic electrochromic devices for energy-saving and smart display applications.

Poly(3,4-ethylenedioxythiophene) (PEDOT)/graphene oxide (GO) hybrid nanostructures have been obtained by an in situ electro-polymerization process. Field emission scanning electron microscope observation indicates that the hybrid nanostructures consist of uniform and well-dispersed PEDOT nanoparticles integrated on the networked GO nanosheets. Surface chemistry and structure of the hybrid nanostructures have been characterized by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Electrochemical and optical property measurements demonstrate that the hybrid nanostructures exhibit significantly improved electrochromic performance compared with the pristine PEDOT nanostructure. The contrast between coloring and bleaching state of the PEDOT nanostructure at 480 nm increases from 23.4% to 31.4% after hybridizing with GO nanosheets. The coloring time and bleaching time are shortened from 1800 ms to 300 ms and 1500 ms to 400 ms, respectively, while the coloring efficiency increases from 53.5 cm2 C−1 to 64.9 cm2 C−1 after the hybridization. The obtained PEDOT/GO hybrid nanostructures promise great potential in developing novel electrochromic materials for smart windows and other energy saving applications.

The exploration of novel nanomaterials employed as substrate to construct glucose biosensors is still of significance in the field of clinical diagnosis. In this work, NiO/Mn 2 O 3 nanoflake arrays were synthesized by hydrothermal approach in combination with calcination process. As-prepared NiO/Mn 2 O 3 nanoflake arrays were utilized to construct electrochemical biosensors for glucose detection. NiO/Mn 2 O 3 nanoflake arrays were investigated systematically by scanning electron microscopy (SEM), X-ray diffractionmeter (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy, the formation mechanism of NiO/Mn 2 O 3 nanoflake arrays was proposed. As-prepared glucose biosensors based on NiO/Mn 2 O 3 nanoflake arrays were characterized by cyclic voltammgrams and chronoamperometry. The results indicated that glucose biosensors based on optimized NiO/Mn 2 O 3 nanoflake arrays exhibited a high sensitivity of 167.0 μA mM −1 Cm −2 and good anti-interference ability, suggesting the NiO/Mn 2 O 3 nanoflake arrays are an attractive substrate for the construction of oxidase-based biosensors.

High-performance battery-type electrodes based on TiO 2 nanotube arrays decorated with Co 0·12 Ni 1·88 S 2 @Co 8 S 9 (CNCS) nanoparticles have been successfully prepared in this paper. The highly conductive TiO 2 nanotube arrays modified with carbon and oxygen vacancies (Ti 3+ defects) ( m -TNAs) are selected as the three-dimensional backbones to support electroactive materials and offer direct pathways for electron and ions transport. Then CNCS nanoparticles are electrodeposited on each nanotube uniformly, and the loading mass of nanoparticles can be controlled through adjusting electrodeposition cycles. After optimization, a remarkable specific capacity of 680.1 C g −1 is achieved at 2 A g −1 as a result of the intrinsic synergetic contributions from structural/compositional/componental merits. This specific capacity is much higher than most of the TNAs-based energy storage electrodes. In addition, an asymmetric supercapacitor device is assembled by applying the optimized CNCS/m-TNAs and commercial active carbon as positive and negative electrode, respectively. It displays a high energy density of 45.5 Wh kg −1 at a power density of 400.5 W kg −1 , after cycling for 3000 cycles at a high current density of 4 A g −1 , the specific capacitance could still remain 85.7%. This self-supported and binder-free CNCS/m-TNAs electrode will be a competitive and promising candidate for the application in energy storage.

In this work, a novel hybrid structure of tungsten nitride nanorods upon graphene nanosheets was obtained by synthesizing WOx nanorods/graphene oxide (GO) nanosheets followed by hydrogenation and nitridization treatment. Electron microscopy and X-ray diffraction results indicated that the hybrid was composed of W2N nanorods and reduced graphene oxide nanosheets. Surface chemical characteristics of the hybrid were characterized by X-ray photoelectron spectroscopy (XPS) and its electrocatalytic activities were evaluated using a rotating disk electrode measurement system. Compared to the WO3 nanorods-GO hybrid, onset potential of the W2N nanorods-rGO hybrid for oxygen reduction reaction (ORR) was shifted from 0.6 V to 0.71 V, and the limiting current density increased by 1.4 times, exhibiting significantly enhanced electrocatalytic performance, which rendered the W2N-rGO hybrid as a potential non-precious-metal ORR catalyst in fuel cells and metal air battery applications.

Rational design and fabrication of novel electrode materials are of great importance for developing supercapacitors with remarkable capacitance and enhanced cycling stability. In this paper, we present a simple one-pot hydrothermal deposition followed by calcinations process for the in situ construction of homogeneous NiO/MnO2/CeO2 (NMC) nanoflake arrays on Ni foam substrate, which could be directly adopted as the binder-free electrode materials for high performance supercapacitors. The field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) are carried out to investigate the morphology, microstructure and composition of NMC nanoflake arrays. As-prepared hierarchical NMC nanoflake arrays exhibit the specific capacitance of 1027.8 F g−1 at a current density of 3.1 A g−1 and excellent cycling stability of 97.8% after 5000 charge/discharge cycles. This facile, cost-effective and controllable fabrication route and the robust supercapacitive activity suggest that the ordered NMC nanoflake arrays could be promising candidate electrode materials for high performance electrochemical energy storage devices.

We studied the growth of copper oxide nanosheet arrays on copper foil via a simple anodization method. The structures, morphologies, and elemental compositions of the specimens were characterized with an X-ray diffractometer, scanning electron microscope, high resolution transmission electron microscope, and X-ray photoelectron spectrometer. The copper oxide (Cu 2 O and CuO) nanosheet arrays were comprised of 30-nm-thick nanosheets that stand vertically on the Cu substrate. The anodizing parameters, such as the current density, temperature, and polyethylene glycol concentration, were optimized to obtain the regular nanosheet arrays. The optical absorption properties of the anodized products were evaluated using a diffuse reflectance spectrometer, and broad and strong optical absorption bands arising from the UV to visible region were observed. The photoelectrochemical performance of the nanosheet arrays was measured with chronoamperometry and cyclic voltammetry on an electrochemical workstation equipped with a Xe lamp (wavelength >400 nm). A negative photocurrent was obtained due to the p-type semiconductor of the copper oxides. The copper oxide nanosheet arrays achieve the highest photocurrent of 0.4 mA/cm 2 at the current density of 1.0 A/dm 2 , temperature of 70 °C, and polyethylene glycol concentration of 0.5 g/L.

Highly ordered TiO2 nanotube arrays (TNAs) with large specific surface exhibit excellent electrochemical performance but their poor electrical conductivity limits the practical applications in supercapacitor. Here, we present a simple strategy for improving the electrical conductivity of TNAs by introduction of oxygen vacancies in NaBH4 aqueous solution. The reduced TNAs (rTNAs) electrodes exhibit significant improvement on electrical conductivity and carrier density compared to those of the pristine TNAs. Interestingly, the rTNAs electrode obtained from 5 M NaBH4 aqueous solution exhibits the highest specific capacitance of 23.24 mF cm−2 at a scan rate of 2 mV s−1 with outstanding long term cycling stability. Moreover, the reduced MnCo2O4/TNAs electrodes are also prepared by a facile chemical bath deposition method and then reduced in NaBH4 aqueous solution. The reduced MnCo2O4/TNAs electrode prepared in 5 M NaBH4 aqueous solution achieves a high specific capacitance of 484.35 mF cm−2 at a scan rate of 2 mV s−1. The enhancement of capacitance and cycling stability of reduced MnCo2O4/TNAs electrodes can be attributed to the improved electrical conductivity of MnCo2O4/TNAs by introduction of oxygen vacancies and the tubular structure of TNAs that accelerate the electron and ions transport.

Nonstoichiometric CeO 2 @CNT core/shell nanowire arrays (NWAs) were synthesized by hydrothermal method in combination with chemical vapor deposition. Morphology and microstructure of the core/shell NWAs were characterized by SEM, XRD, TEM and Raman spectrum techniques. The novel nonstoichiometric CeO 2 @CNT core/shell NWAs were employed as substrates to construct cholesterol electrochemical biosensors. They showed high sensitivity of 336.6 μA cm −2 mM −1 and low detection limit of 7.4 µm towards cholesterol detection at working potential of −0.4 V due to synergistic effect of nonstoichiometric CeO 2 and CNT, and they also demonstrated excellent selectivity towards interferents co-existing with cholesterol in blood serum.

Via a facile one-step chemical bath deposition route, homogeneously dispersed Mn 3 O 4 nanoparticles have been successfully deposited onto the inner surface of TiO 2 nanotube arrays (TNAs). The content and size of Mn 3 O 4 can be controlled by changing the deposition time. Field emission scanning electron microscopy and transmission electron microscopy analysis reveal the morphologies structures of Mn 3 O 4 /TNAs composites. The crystal-line structures are characterized by the X-ray diffraction patterns and Raman spectra. X-ray photoelectron spectroscopy further confirms the valence states of the sample elements. The electrochemical properties of Mn 3 O 4 /TNAs electrodes are systematically investigated by the combine use of cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The resulting Mn 3 O 4 /TNAs electrode prepared by deposition time of 3 h shows the highest specific capacitance of 570 F g −1 at a current density of 1 A g −1 . And it also shows an excellent long-term cycling stability at a current density of 5 A g −1 , which remaining 91.8% of the initial capacitance after 2000 cycles. Thus this kind of Mn 3 O 4 nanoparticles decorated TNAs may be considered as an alternative promising candidate for high performance supercapacitor electrodes.

One-dimensional (1D) carbon materials have attracted much attention based on their great potential applications in lithium/sodium-ion (Li+/Na+) storage, heteroatom doping (such as N doping) and architecture design could further improve their electrical conductivity, diffusion kinetics and Li+/Na+ storage capacities. Herein, 1D porous carbon@N-doped porous carbon (PC@NPC) core-shell nanowires derived from two different kinds of metal-organic frameworks precursors, Mn-BTC@ZIF-67 and Mn-BTC@ZIF-8 core-shell nanowires, are reported in this work. N content, specific surface area, pore size and graphitic degree have been systematically investigated by adjusting the carbonization temperatures. PC@NPC-67 derived from Mn-BTC@ZIF-67 shows superior energy storage performance compared to PC@NPC-8 originated from Mn-BTC@ZIF-8, and PC@NPC-67-600 °C delivers an optimum reversible Li+ storage capacity of 811.9 mAh g−1 at 0.1 A g−1 (for the 10th cycle), as well as excellent rate performance (291.7 mAh g−1 at the high rate of 10 A g−1) and outstanding cycling stability (97.8% specific capacity retention after 500 cycles at a high density of 1 A g−1). Meantime, it also displays high Na+ storage capacity, good rate performance and excellent cycling stability. The as-prepared functional materials will be competitive and promising candidate for electrochemical energy storage and other applications.

Binder-free, high-performance electrode materials play a critical role for supercapacitors. In this paper, through the electrochemical anodization process, ordered CuO/Cu2O nanosheet arrays (NSAs) were successfully in situ fabricated on copper foil, which could be directly adopted as the current collector. Then, NiOOH was introduced for the further modification of CuO/Cu2O arrays via a facile hydrothermal deposition treatment using nickel nitrate as precursor. The as-fabricated NiOOH@CuO/Cu2O composite nanosheet arrays exhibit an excellent areal capacitance of 1206 mF cm−2 at a current density of 1 mA cm−2 in 2 M KOH aqueous solution with an outstanding long-term cycling stability, with 84.6% of initial capacitance after 3000 charge/discharge cycles. The facile, cost-effective, and controllable fabrication route and the robust supercapacitive activity suggest that the NiOOH@CuO/Cu2O composite nanosheet arrays could be a promising candidate electrode material for high-performance supercapacitors.

Highly ordered TiO2 nanotube arrays (TNTAs) have shown great promise to serve as an efficient current collector as well as an outstanding support for the application of constructing high performance supercapacitor electrode materials. In this study, a novel-structured MnO2/EH-TNTAs electrode with superior supercapacitive performance was developed by galvanostatic electrodeposition of MnO2 nanoflakes onto both the outer and inner walls of electrochemically hydrogenated TNTAs (EH-TNTAs). The as-fabricated MnO2/EH-TNTAs electrode could achieve a specific capacitance of up to 650.0 F g−1 at 1.0 A g−1 with 86.9% of the initial capacitance remaining after 5000 charge/discharge cycles at 5 A g−1, outperforming other reported TNTAs-based electrodes. The prominent supercapacitive performance of MnO2/EH-TNTAs electrode could be attributed to the unique 3D cotton-like porous structure and high specific surface area of MnO2 deposit as well as the remarkably improved electrical conductivity and electrochemical performances of EH-TNTAs induced by the introduction of oxygen vacancies during the electrochemical hydrogenation process. This work offers theoretical insight and practical guidelines for TNTAs-based electrodes applied for high-performance supercapacitors as well as other energy storage devices.

Self-supported and binder-free electrodes based on homogeneous Co3O4/TiO2 nanotube arrays enhanced by carbon layer and oxygen vacancies (Co3O4/co-modified TiO2 nanotube arrays (m-TNAs)) are prepared via a simple and cost-effective method in this paper. The highly ordered TNAs offer direct pathways for electron and ion transport and can be used as 3D substrate for the decoration of electroactive materials without any binders. Then, by a facile one-step calcination process, the electrochemical performance of the as-obtained carbon layer and oxygen vacancy m-TNAs is approximately 83 times higher than that of pristine TNAs. In addition, Co3O4 nanoparticles are uniformly deposited onto the m-TNAs by a universal chemical bath deposition (CBD) process to further improve the supercapacitive performance. Due to the synergistic effect of m-TNAs and Co3O4 nanoparticles, a maximum specific capacitance of 662.7 F g−1 can be achieved, which is much higher than that of Co3O4 decorated on pristine TNAs (Co3O4/TNAs; 166.2 F g−1). Furthermore, the specific capacitance retains 86.0 % of the initial capacitance after 4000 cycles under a high current density of 10 A g−1, revealing the excellent long-term electrochemical cycling stability of Co3O4/m-TNAs. Thus, this kind of heterostructured Co3O4/m-TNAs could be considered as promising candidates for high-performance supercapacitor electrodes.

In this paper, we reported construction of CuO/Cu 2 O@CoO core-shell nanowire arrays by combining a chemical deposition method and post-thermal annealing process on Cu foil without any binders and conductive additives. The nanowire arrays were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDX) techniques. The determination results indicate that the nanowire arrays are distinct CuO/Cu 2 O nanowire core decorated with branched CoO nanosheet shells. In addition, the as-obtained nanowire arrays demonstrate outstanding areal capacitance of 280 mF cm − 2 at a current density of 1 mA cm − 2 as well as superior cycling stability which remains 90.7% of initial capacitance after 3000 cycles. The facile and cost-effective synthesis integrated with the robust electrochemical performances suggests that the CuO/Cu 2 O@CoO core-shell nanowire arrays are expected to be promising candidate electrodes for high-performance supercapacitor and other energy storage applications.

In this present work, we report a mild and efficient chemical route in preparing Fe3O4@ZnS bifunctional nanospheres. Scanning electron microscopy (SEM) observation and X-ray diffraction (XRD) indicate core-shell structure of the Fe3O4@ZnS nanospheres with the diameter around 400–700 nm. High-resolution transmission electron microscopy (HRTEM) determination reveals high crystallinity of the nanospheres. Magnetic and photoluminesce properties of the nanospheres show that the nanospheres possessed high magnetization saturation value of 58.8524 ∼61.6569 emu/g with strong blue emission under UV irradiation. The optical intensity can be adjusted in our experiments. These properties suggest that the bifunctional magnetic-optical nanospheres promise great potential in the applications of optical imaging and time-resolved fluorescence imaging.

Porous Co 3 O 4 nanowire array has been in-situ grown on the La 0.8 Sr 0.2 MnO 3−δ (LSM) electrode by a facile hydrothermal process aiming at enhancing the electrochemical performance of LSM anode for steam electrolysis in intermediate temperature proton-conducting solid oxide electrolyzer. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques have been employed to characterize phase structure, morphology and composition of the obtained hybrid. The high activity of the Co 3 O 4 nanoarray improves the oxygen reduction performance of LSM at intermediate temperature. Significant improvement has been obtained in terms of catalytic activity of the hybrid electrode compared with bare LSM electrode in air. The maximum current efficiency of the hybrid electrode reaches 71.64% for steam electrolysis in a proton-conducting solid oxide electrolyzer at 700 °C, which is approximately 1.3 times higher than that for the bare LSM electrode.

Carbon nanotubes (CNTs) and reduced graphene oxide (rGO) nanosheets were utilized to construct glucose biosensors in combination with gold nanowire arrays (AuNWAs), and microfluidic injection analysis driven by gravity force was used to investigate the performances of as-prepared glucose biosensors. The results demonstrated glucose biosensors based on carbon nanomaterials/AuNWAs presented excellent performance at low working potential of −0.2 V versus Ag/AgCl (3 mol/L KCl), such as high sensitivity, good anti-interference ability and high throughput (45 h−1). The glucose biosensor based on glucose oxidase (GOx)–CNT–AuNWAs showed a wide linear range from 100 to 3,000 µmol/L with a sensitivity of 4.12 µA/cm2 mmol/L. Furthermore, the linear range and sensitivity of GOx–rGO–AuNWAs-based glucose biosensor were 50–4,000 µmol/L and 8.59 µA/(cm2 mmol/L), respectively, which were better than those of glucose biosensor based on GOx–CNT–AuNWAs, suggesting rGO nanosheets in combination with AuNWAs being a good platform for the construction of glucose biosensors.

Single atom catalysts (SACs) are widely researched in various chemical transformations due to the high atomic utilization and catalytic activity. Carbon-supported SACs are the largest class because of the many excellent properties of carbon derivatives. The single metal atoms are usually immobilized by doped N atoms and in some cases by C geometrical defects on carbon materials. To explore the catalytic mechanisms and improve the catalytic performance, many efforts have been devoted to modulating the electronic structure of metal single atomic sites. Doping with polynary metals and heteroatoms has been recently proposed to be a simple and effective strategy, derived from the modulating mechanisms of metal alloy structure for metal catalysts and from the donating/withdrawing heteroatom doping for carbon supports, respectively. Polynary metals SACs involve two types of metal with atomical dispersion. The bimetal atom pairs act as dual catalytic sites leading to higher catalytic activity and selectivity. Polynary heteroatoms generally have two types of heteroatoms in which N always couples with another heteroatom, including B, S, P, etc. In this Review, the recent progress of polynary metals and heteroatoms SACs is summarized. Finally, the barriers to tune the activity/selectivity of SACs are discussed and further perspectives presented.

Uric acid (UA) is an important indicator for human metabolism, therefore it is of great significance to develop a sensitive and selective biosensor for monitoring UA and diagnosing relevant disorders. In this paper, porous Cu2O/Cu@C core-shell nanowires (NWs) are synthesized by thermal decomposition of HKUST-1 NWs. Subsequently the nanowires are used as electrode materials to fabricate UA biosensors. By controlling the conditions of calcination, we obtain composite particles consisting of cuprous oxide and copper nanoparticles which are wrapped within the nanowire shell formed by non-graphitic carbon material. These nanowires exhibit excellent electrocatalytic capability at low working potential that is beneficial for improving the anti-interference ability of UA biosensors. Furthermore, carbon and copper in the substrate accelerate electron transfer to substantially improve the sensitivity of the UA biosensors. Sensitivity of 330.5 μA·mM−1·cm−2 and a linearity range from 0.05 to 1.15 mM (R2 = 0.997) at a working potential of −0.5 V vs SCE are achieved. We also demonstrate the practicality of our biosensors for clinical applications by measuring the concentration of UA in diluted human urine.

In this work, hollow spherical nickel-cobalt coordination polymer (Ni–Co/CP) have been synthesized. The hollow structure would facilitate the transport of ions, meanwhile the lamellar sheets may provide more active sites, which are of benefit to achieve high electrochemical performance. The Ni–Co/CP exhibits a high specific capacity of 758.8C g−1 at 0.5 A g−1. At 20 A g−1, the specific capacity is still as high as 584 C g−1. The capacity remains 84.6% of its initial value after 5000 cycles. Furthermore, all-solid-state supercapacitors have been assembled using Ni–Co/CP, polybenzimidazole (PBI) doped with KOH and activated carbons (AC) (Ni–Co/CP//PBI-KOH//AC). A high cell specific capacitance of 166.9 F g−1 have been achieved at 1 A g−1 with applied potential difference up to 1.8 V, which corresponds to a specific energy of 75.1 W h kg−1 at 900 W kg −1; the capacitance retention remains 85.5% after 8000 cycles suggesting the good stability. Moreover, the device with a large size (2*7 cm) exhibits good flexibility under bending and folding conditions. It also exhibits a cell specific capacitance of 169.5 F g-1 at 0.5 A g−1. These results indicate that the Ni–Co/CP and PBI based flexible all-solid-state supercapacitors are very competitive in the future applications of flexible and wearable electronics.

Decorated TiO2 nanotube array-based electrodes for supercapacitors are successfully fabricated by a facile and green process in this paper. Firstly, TiO2 nanotube arrays are modified with ultrathin carbon layers by in situ pyrolysis with residual ethylene glycol from anodization as a carbon resource, then electroactive materials, nickel cobalt oxides with different stoichiometric nickel and cobalt contents, are synthesized by chemical bath deposition and a controlled post-calcination process. The sample demonstrates a superb specific capacitance of 934.9 F g−1 at a current density of 2 A g−1 and a better rate capability of 865.8 F g−1 at 20 A g−1 while maintaining 92.6% capacity after 5000 cycles at a high current density of 10 A g−1. The outstanding supercapacitive performance is attributed to the unique hierarchical mesoporous architectures and the desirable design of the nanocomposites, and it also suggests that carbon modified TiO2 nanotube arrays decorated with nickel cobalt oxides are promising candidates for supercapacitor applications.

Highly ordered TiO2 nanotube arrays (TNAs) with enhanced electronic conductivity treated by introducing oxygen vacancies have been considered to be a promising electrode material for supercapacitors. In this work, we fabricated electrochemically doped TiO2 nanotube arrays (ED-TNAs) through a facile cyclic voltammetry method, and then deposited the uniformly dispersed Cu2O nanoparticles onto ED-TNAs to synthesise a high performance electrode for a supercapacitor. The ED-TNAs electrode exhibited a high specific capacitance of 5.42 mF cm−2 at a scan rate of 10 mV s−1, which was about 59 times higher than for the pristine TNAs electrode. Moreover, the ED-TNAs were demonstrated to be an appropriate support for Cu2O nanoparticles. The highest specific capacitance of the Cu2O/ED-TNAs electrode could reach 198.7 F g−1 at the current density of 0.2 A g−1, and approximately 88.7% of the initial capacitance was retained after 5000 cycles of galvanostatic charge–discharge.