Nanotube Array Electrode Research Articles

Effect of heat-treatment atmosphere on the current generation of TiO2 nanotube array electrodes in microbial fuel cells

We investigated the effects of the heat-treatment atmosphere on the current generation of Ti electrodes in microbial fuel cells (MFCs). The maximum current density was achieved for TiO2 nanotube array electrodes heated in H2 (TNA-H2) (22.69±0.18Am−2). Physical analysis of the Ti electrode surfaces revealed that the specific surface area increased after electrochemical anodization. The crystallinities of the TiO2 nanotube array electrodes heated in H2 (81.66%), CH4 (74.48%), N2 (59.67%), and O2 (44.82%) showed a significant positive correlation with the corresponding current densities (P<0.05, R2=0.9469). In addition, the highest electron transfer rate constant was achieved for TNA-H2 (2.38s−1). The large specific surface area, good chemical stability, high electron transfer rate, and good biocompatibility of TNA-H2 suggest its great potential for application as an anode system in MFCs.

Engineering Highly Ordered Iron Titanate Nanotube Array Photoanodes for Enhanced Solar Water Splitting Activity

Highly ordered iron titanate (Fe2TiO5) nanotube array photoanode is synthesized on F:SnO2 glass with ultrathin anodized aluminum oxide as a hard template. Highly crystalline, yet the nanotube array morphology‐preserved Fe2TiO5 is fabricated by hybrid microwave annealing (HMA). The effects of the synthesis parameters on photoelectrochemical (PEC) water splitting activity under simulated sunlight are systematically studied including HMA time, pore size, wall thickness, and length of the nanotubes to optimize the nanotube array photoanode. In addition, triple modification strategies of TiO2 underlayer, hydrogen treatment, and FeNiOx cocatalyst loading effectively improve the PEC activity further. The systematically engineered nanotube array photoanode achieves a photocurrent density of 0.93 mA cm−2 at 1.23 VRHE under 1 sun (100 mW cm−2) irradiation, which corresponds to 2.6 times that of the previous best Fe2TiO5 photoanode. In addition, the photocurrent onset potential shifts cathodically by ≈280 mV relative to the pristine nanotube array electrode.

Tuning Ag morphology on TiO2 nanotube arrays by pulse reverse current deposition for enhanced plasmon-driven visible-light response

TiO2 nanotube arrays (NTAs) decorated with controllable Ag particles were prepared by pulse reverse current deposition in AgNO3/NaNO3 aqueous solution, aiming to improve the photoelectrochemical properties of TiO2 NTA electrode in visible-light region. By tuning the pulse current density and deposited charge density, a controllable synthesis of Ag structures was achieved. Excellent photocurrent responses of TiO2 NTAs in UV and visible light regions were achieved by depositing Ag nanorods and nanoparticles, which was attributed to highly efficient charge separation by the Schottky junction at the Ag/TiO2 interface and localized surface plasmon resonance effect of Ag nanostructures.

Sulfonated poly(phenylene oxide)/Ti3+/TiO2 nanotube arrays membrane/electrode with high performances for lithium ion battery

Sulfonated poly(phenylene oxide) (SPPO) film was electrodeposited on Ti3+-doped TiO2 nanotube arrays (Ti3+/TiO2NT) electrode via the electropolymerization of sulfonated phenol. The as-synthesized SPPO/Ti3+/TiO2NT membrane/electrode was investigated in terms of SEM, FESEM, EDX, FTIR, XPS, galvanostatic charge/discharge, and cycle voltammetry (CV). As expected, the porous SPPO film did form on the surface of Ti3+/TiO2NT electrode; furthermore, the resultant SPPO/Ti3+/TiO2NT membrane/electrode delivered higher electrochemical performances than PPO/Ti3+/TiO2NT, mainly attributed to the contributions of the ionic conductivity induced by –SO3H groups within SPPO.

Preparation of carbon dots/TiO2 electrodes and their photoelectrochemical activities for water splitting

Carbon dots with various functional groups can be employed as the potential sensitizer. In this study, carbon dots are obtained by electrochemical ablation of graphite rods in alkaline electrolyte. The better preparation condition is the applied potential of 40 V and the ablation time of 5 h. TiO2 nanotube arrays and TiO2 nanoparticles photoelectrodes are sensitized by the as-prepared carbon dots through using impregnation method. Carbon dots/TiO2 nanotube arrays electrodes exhibit greater photoelectrochemical hydrogen production activities than carbon dots/TiO2 nanoparticles electrodes. It is because more carbon dots can be well combined with TiO2 nanotube arrays. Based on the IPCE values in visible light region, the role of carbon dots on TiO2 nanotube arrays electrode depends on the up-converted PL behaviors from their surface states and the alkaline electrolyte. The results provide insight into carbon dots that serve as sensitizer of TiO2 photoelectrode in water splitting system of alkaline solution.

新型Cu/Cu&lt;sub&gt;2&lt;/sub&gt;O/TiO&lt;sub&gt;2&lt;/sub&gt;电极检测糖含量的研究

本实验采用二次阳极氧化结合简单的电沉积方法制备新型Cu/Cu2O/TiO2(CCT)电极。我们通过扫描电镜(SEM)、X射线衍射仪(XRD)和电化学工作站对产物的形貌、晶相和电催化性能进行了表征，发现簇状大颗粒形貌的Cu/Cu2O分散在TiO2纳米管中。通过对比研究电极在0.1 M NaOH溶液条件下，分别对葡萄糖、果糖和蔗糖的电催化氧化结果。可以发现葡萄糖的催化氧化电流最高，而果糖的氧化电位最低，蔗糖的催化氧化性能最差。使用该电极能分别检测较低浓度的三种糖，其中对果糖检测性能最好，其线性响应范围为0~3.5 mM (R2 = 0.99)，灵敏度为3560 µA cm−2•mM−1，检测限(LOD)为1.3 µM。该电极对葡萄糖与果糖混合溶液的最高氧化电流密度可达8 mA cm−2，表现出了相当好的电催化氧化性能，未来有望在糖类燃料电池领域得到应用。 Cu/Cu2O/TiO2 (CCT) nanotube arrays electrode has been fabricated by secondary anodic oxidation combination of electrodeposition method. The structure and morphology of the CCT were charac-terized by X-ray diffraction (XRD) and Scanning electron microscope (SEM) respectively and the electrochemical performances of the electrode were performed on electrochemical workstation. The SEM result showed that the large sized, cluster-liked Cu/Cu2O particles have dispersed in CCT nanotubes. When the electrode was used as electrocatalytic oxidation of the glucose, fructose and sucrose under 0.1 M of NaOH aqueous solution, the tested results showed that the glucose has the highest oxidated current, the fructose has the lowest oxidated electric potential but the sucrose has the poorest electrocatalytic oxidation performance among these three saccharides. Moreover, when the electrode was utilized as detection for the low concentrations of saccharides, the electrode showed excellent detection performance for fructose. Its linear response could reach up to 3.5 mM (R2 = 0.99) with detection limit of 1.3 μM (signal/noise = 3) and the sensitivity is 3560 µA cm−2•mM−1. Meanwhile, the electrode showed outstanding electrocatalytic oxidation performance that the oxidation electric current could reach to 8 mA cm−2 for the glucose and fructose mixed aqueous solution. The electrode had the potential application prospect and expected to be applied in carbohydrate fuel cells.

Electrochemical Performance of Anatase TiO2 Nanotube Arrays Electrode in Ionic Liquid Based Electrolyte for Lithium Ion Batteries

Ternary electrolyte composed of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (PYR14TFSI), γ-butyrolactone (GBL) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and anatase TiO2 nanotube arrays (NTAs) electrode are investigated for the application in new generation of lithium-ion batteries (LIBs). The electrical conductivity and viscosity are measured in the whole composition range at several temperatures. Also, cyclic voltammetry experiments are performed at different temperatures and scan rates. At all scan rates, up to 100 mV·s−1 Ti4+/Ti3+ redox peaks appear designating exceptionally fast intercalation/deintercalation reaction. At the end of cycling the intercalation/deintercalation capacity was 144.8/140.7 mAh·g−1 at current rate 3 C. The diffusion coefficient for Li+ extraction from TiO2 nanotubes (NTs) have been calculated for temperatures from (25 to 55) °C. Activation energy for diffusion was found to be 54.7 kJ/mol (0.57 eV).

A Pt/TiO2 Nanotube Array Electrode for Glucose Detection and Its Photoelectrocatalysis Self-Cleaning Ability

A non-enzymatic amperometric glucose sensor was prepared based on Pt-decorated TiO2 nanotube array (NTA). TiO2 NTA was obtained through anodization, and Pt nanoparticles were loaded onto the TiO2 NTA by ion exchange. The prepared electrode exhibited a decent sensitivity of 1.01386 × 10−4 A mM−1 cm−2 at a very low potential and a detection limit of 0.2 mM glucose at a signal-to-noise ratio of 3. The mechanism of glucose electrocatalytic oxidation was also examined and a two-electronic decomposition reaction was observed. It was found that the electrode possessed outstanding self-cleaning ability such that it can be restored and used stably after being contaminated. Details of the self-cleaning process were further explored, and the polluted electrode proved to be able to clean itself after 50 cycles of cyclic voltammetry from –0.7 V to 1 V at 2.8 mW/cm2 light intensity at wavelength of 365 nm. The research results shed new light on glucose detection with Pt/TiO2 NTA electrode and provide a new way to renew the electrode surface by photoelectrocatalysis self-cleaning.

Flake-like Cu2O on TiO2 nanotubes array as an efficient nonenzymatic H2O2 biosensor

This work provides a new method for fabrication of the flake-like Cu2O/TiO2 nanotubes array (TNA) electrode as a H2O2 sensor. The flake-like Cu2O/TNA electrode was successfully constructed by potentiostatic electrodeposition combining subsequent cyclic voltammetry (CV) technology in NaOH solution. The catalytic performance of the sensor was studied in 0.1M phosphate buffer (PBS, pH=7.4). It was found that the flake-like Cu2O/TNA electrode displayed a good catalytic performance towards the reduction of H2O2 with a response time of 4s, a wide linear dependence on a concentration of H2O2 from 0.5mM to 8mM, a good sensitivity of 412.11μAcm−2mM−1 and a detection limit of 90.5μM at a working voltage −0.40V (vs. Hg/Hg2Cl2). The electrocatalytic mechanism of the flake-like Cu2O/TNA electrodes was also proposed.

Enlarged capacitance of TiO2 nanotube array electrodes treated by water soaking

Anodic TiO2 (ATO) nanotube arrays have been considered as promising electrode materials for super capacitors. However, their specific capacitance value is still not comparable with conventional super capacitor materials. Here, we demonstrate a convenient method for improving the capacitive properties of ATO nanotube arrays for super capacitors, which can be realized simply by soaking the as-anodized ATO nanotube arrays in water at room temperature for a sufficiently long time. The nanotube wall for the soaked ATO nanotube arrays becomes rough, resulting in increased specific surface area. After an electrochemical hydrogenation doping process using potentiodynamic cycling for the ATO samples, the soaked ATO electrodes exhibit a very high average specific capacitance of 20.96 mF cm−2 at a current density of 0.05 mA cm−2, about a threefold improvement over those unsoaked ones that just treated by the electrochemical hydrogenation doping. The presented results demonstrate that the soaking treatment is a facile and cost-effective way to change the morphology of ATO nanotubes and increase specific capacitance, which would be of great industrial interest.

Synthesis and Stabilization of Blue-Black TiO2 Nanotube Arrays for Electrochemical Oxidant Generation and Wastewater Treatment.

Efficient, inexpensive, and stable electrode materials are key components of commercially viable electrochemical wastewater treatment system. In this study, blue-black TiO2 nanotube array (BNTA) electrodes are prepared by electrochemical self-doping. The 1-D structure, donor state density, and Fermi energy level position are critical for maintaining the semimetallic functionality of the BNTA. The structural strength of the BNTA is enhanced by surface crack minimization, reinforcement of the BNTA-Ti metal interface, and stabilized by a protective overcoating with nanoparticulate TiO2 (Ti/EBNTA). Ti/EBNTA electrodes are employed as both anodes and cathodes with polarity switching at a set frequency. Oxidants are generated at the anode, while the doping levels are regenerated along with byproduct reduction at the cathode. The estimated maximum electrode lifetime is 16 895 h. Ti/EBNTA has comparable hydroxyl radical production activity (6.6 × 10-14 M) with boron-doped diamond (BDD, 7.4 × 10-14 M) electrodes. The chlorine production rate follows a trend with respective to electrode type of Ti/EBNTA > BDD > IrO2. Ti/EBNTA electrodes operated in a bipolar mode have a minimum energy consumption of 62 kWh/kg COD, reduced foam formation due to less gas bubble production, minimum scale formation, and lower chlorate production levels (6 mM vs 18 mM for BDD) during electrolytic wastewater treatment.

Experimental Study on the Plant Dye Sensitized TiO&lt;sub&gt;2&lt;/sub&gt; Electrode

In this paper, Ti sheets were anodized to obtain TiO2 nanotube arrays electrodes. The impact of different oxidation conditions on photoelectric properties of TiO2 nanotube arrays were discussed by the photocurrent density, and the optimal oxidation conditions of TiO2 which had good photoelectric properties were found. Pigments were extracted from fresh spinach leaves, tomatoes and carrots, and to be used as plant dye to sensitize TiO2 electrodes. The photocurrent density and the Incident Photon to Current Efficiency (IPCE) of the plant dye sensitized TiO2 electrodes were examined.

Fabrication of Cd0·5Zn0·5S nanoparticles decorated TiO2 nanotube arrays electrode and its enhanced photoelectrocatalytic performance

Cd0·5Zn0·5S nanoparticles modified TiO2 nanotube arrays composite electrodes (Cd0·5Zn0·5S/TiO2 NTAs) were successfully synthesized by the combination of electrochemical oxidation and hydrothermal process under various thiourea concentrations. The as-prepared electrodes were systematically characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–Vis diffuse reflectance absorption spectra techniques. The influence of thiourea concentrations on the morphology structure, photoelectrochemical properties, and hydrogen production of Cd0·5Zn0·5S/TiO2 NTAs electrodes was systematically investigated. The Cd0·5Zn0·5S/TiO2 NTAs electrode fabricated at 8 mM thiourea concentration exhibits the highest hydrogen production rate of 523.1 μmol/(h∙cm2) and the maximum photocurrent density of 26.73 mA/cm2 under visible light illumination. The corresponding apparent quantum efficiency (QE) and visible-photoconversion efficiency are 55.2% and 11.97%, respectively. Electrochemical impedance spectroscopy (EIS) analysis of Cd0·5Zn0·5S/TiO2 NTAs electrode further demonstrates the enhanced photoelectrochemical performance, which can be attributed to the favorable microstructure and enhanced charge transfer.

Epinephrine sensing at nanostructured Au electrode and determination its oxidative metabolism

Epinephrine (EP) is a neurotransmitter and hormone involved in an enormous number of processes in living organisms, however its highly active oxidation metabolites can cause hard damages and lead to serious health consequences. This paper described a relatively simple method of fabrication of Au nanotube array electrodes for electrochemical determination of EP, which could be easily transferred to non-laboratory conditions. On the basis of Tafel plot, some parameters of EP oxidation process like number of electrons involved in the rate-determining step (nα=2) and electron transfer coefficient (α=0.45) were evaluated for the studied electrode. The linear sweep voltammetry (LSV) revealed a very good linear response in the EP concentration range of 60–600μM EP, however to 1000μM its linearity differs insignificantly. Using differential pulse voltammetry (DPV), the calibration curve for EP determination is close to linear in the range of 10–150μM, but the detection limit of 2.8μM was evaluated for a lower concentration range 10–60μM. The proposed DPV method was successfully applied to the determination of EP in a pure, ascorbic acid containing and real samples. The DPV results were evaluated and compared with those obtained by the high-performance liquid chromatography (HPLC) method. Combining the ROXY™ EC System with mass spectrometry creates an analytical tool for oxidative products of EP and conjugation of EP reactive potential metabolites characterized for I and II stage of biotransformation. The presence of leucoadrenochrome-o-semiquinone radicals confirmed by mass spectrometry implies that the ECE (electron transfer-chemical reaction-electron transfer) mechanism of EP oxidation at the Au electrode is more feasible.

Free-Standing Oxide Nanotube Array Electrodes for High Energy Density and Power Density Li-Ion Batteries

During the past few years, with the increasing power demand generated by applications from portable devices to electric vehicles, more and more emphasis is put on manufacturing high energy and power density Li-ion batteries, i.e., to maximize the capacities while retaining a high rate capability. So far, the studies have been mainly dedicated to the development of powder type electrode materials and relatively little attention has been paid to studies of other electrode architectures. While composite electrodes containing a mixture of the active material powders, binders and conductive additives still are commonly used, such electrodes often yield poor material utilization, undefined material/component arrangements and a lot of complex interfaces. In the present work, we demonstrate that various highly ordered, free-standing oxide nanotube array electrodes, fabricated by electrochemical anodization approaches, can be used either for high energy density and power density Li-ion microbattery applications or as model monolithic electrodes for electrode engineering studies. By using anatase TiO2 nanotube electrodes (as an example of an intercalation type material), an areal capacity of 0.37 mAh cm-2 (i.e., 40 mAh g-1) at a rate of 10C (using a (dis-)charge current density of 9 mA cm-2), and 1 mAh cm-2 (i.e., 91 mAh g-1) at a rate of C/5), can be achieved. [1] Well-defined monolithic anatase TiO2 nanotube electrodes with fine-tuned nanotube size gradients (including tube length, diameter and wall thickness) can also be manufactured using a bipolar electrochemistry approach. [2] The gradient nanotube electrodes can provide excellent rate performance, with capacities from of 0.16 mAh cm-2 or 169 mAh g-1 at a rate of C/5 to 0.04 mAh cm-2 or 42 mAh g-1 at a rate of 50C. In addition, free-standing Nb2O5 nanotube electrodes, which can be cycled for 10000 cycles with only a 20% loss of initial capacities, can provide unprecedented high-rate battery performances, i.e. the capacities from of 0.1 mAh cm-2 or 110 mAh g-1 at a rate of C/5 to 0.04 mAh cm-2 or 44 mAh g-1at a rate of 100C.[3] Some recent work carried out to investigate highly ordered Fe3O4 nanotubular/nanoporous electrodes as a prototype free-standing conversion electrode will also be described.

Photoelectrocatalytic degradation Rhodamine B over highly ordered TiO2 nanotube arrays photoelectrode

Different nanotube length of TiO2 nanotube arrays (NTAs) electrodes was successfully prepared by anodization method with different duration time. The as-prepared electrodes were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Mott-Shottky measurement. The influence of bias potential, illumination and nanotube length on Rhodamine B (RhB) degradation was investigated. The results show that applied bias potential and short nanotube length are beneficial to RhB degradation due to the enhanced charge transfer. Moreover, it is found that an induction period exists in the RhB photoelectrodegradation with short nanotube length and the rate is sensitive to the carriers’ concentration. This can be attributed to the increased effective holes for degradation RhB and the decreased recombination rate of electrons-holes. Nevertheless, RhB photoelectrodegradation with long nanotube length did not display the similar kinetic characteristic. The possible explanation is that long nanotube length increases the recombination rate of electrons-holes and limits the charge transfer, hence decreases the amount of effectively charge carriers. This may decrease the degradation rate and thus result in the disappearing of the second degradation constant. Moreover, we further demonstrate our deduction by the electrochemical impedance spectroscopy (EIS) and Mott-Shottky measurement.

Enhanced electrochemical performance of TiO2 nanotube array electrodes by controlling the introduction of substoichiometric titanium oxides

Although anodized titania nanotubes (TNTs) possess unique advantages as an electrode material, the poor electrical conductivity limits their practical application. We herein report a facile route to enhance electrical conductivity and improve electrochemical behavior by controlling the introduction of substoichiometric titanium oxides (TinO2n-1), which can facilitate charge propagation in TNTs and improve kinetics of ions and electron transport in the electrode. Specific capacitance is as high as 3.77 mF cm−2, which is about 47 times higher than that of the untreated samples (0.08 mF cm−2). Galvanostatic charge-discharge results show TNT arrays-based electrode stable capacitance behavior with excellent capacitance retention even after 1000 continuous charge-discharge cycles at a current density of 50 μA cm−2 in Li2SO4 electrolyte. The ease of synthesis and the superior electrochemical performance suggest a promising application for the TNT arrays-based material in energy storage field.

Study on Fabrication and UV Photoelectric Property of TiO2 Nanotube Array Electrodes

Highly ordered TiO2 nanotube array electrodes were successfully fabricated by a two-step anodization method on Ti sheet substrates in an electrolyte composed of ammonium fluoride, deionized water, and glycol. The tube wall was smooth, and the average internal and external diameters, wall thickness, and tube length achieved were 80 nm, 90 nm, 10 nm, and 9 µm, respectively. X-ray diffraction and field emission scanning electron microscopy results revealed that the TiO2 nanotube arrays presented an amorphous structure. When calcined at 300 °C, the arrays crystallized into the anatase phase, and the crystallization degree of the oxide layer increased as the temperature rose. Calcinating at 400 °C did not obviously disrupt the porous structure of the highly ordered arrays. However, higher temperature enlarged the diameter of the nanotube array and roughened the tube wall. When the temperature reached 600 °C, the nanotube mouth broke because of the excessive stress, causing the oxide layer's thinness and nanotube mouth clogging. The photoelectric test showed that the electrode presented obvious photoresponse under 300-400 nm UV excitation (maximized at 360 nm). The degree of crystallization and the micro-structure of the oxide layer can significantly affect the photoelectric properties of the electrode. After calcination at 400 °C, the TiO2 nanotube arrays, with highly ordered tubular structure directly connected to the Ti substrate, can ensure the rapid transportation of photo-induced electrons to the Ti substrate, while the high crystallinity of the arrays can help reduce the defect density of the nanotube and extend the lifetime of the photo-induced carriers. The electrode showed the best photoelectric property, and the photocurrent intensity was maximized (29.6 µA). However, the calcination process with over-temperature resulted in substantial loss of the TiO2 oxide layer, mouth clogging, and a severe decline in the photoelectric properties.

Ti/TiO2 nanotube array electrode as a new sensor to photoelectrocatalytic determination of ethylene glycol

The photoelectrocatalytic oxidation behaviour of ethylene glycol (EG) was studied in the present work using the TiO2-modified Ti foil (Ti/TiO2) electrode. The Ti/TiO2 nanotube array (Ti-NTA) electrode was prepared by anodizing of the Ti foil in the HF aqueous solution (0.2% v/v). The anodization was conducted in the constant 30 V for 2 h, and then the as-prepared Ti-NTA electrode was calcinated at 50 ∘C for 2 h. The surface morphology of Ti- NTA electrode was studied using scanning electron microscopy images. For EG determination, the photocurrent of EG (EG oxidation current in the UV irradiation) was assessed using the hydrodynamic photoamperometric method in the phosphate buffers. Ultimately, the optimum conditions of EG determination were studied in various pH values and applied bias potentials, and the pH = 3.0 and E= 1.0 V (vs. reference electrode) were determined as the optimum conditions. It was found that the photocurrent of EG was linearly dependent on the concentration of EG in the range of 3.0 × 10 −5 to 0.88 mol l −1, and the detection limit of EG determination was found to be 7.2 × 10−6 mol l−1 (3 σ).

Fabrication of TiO2@MnO2 nanotube arrays by pulsed electrodeposition and their application for high-performance supercapacitors

The fabrication of TiO2@MnO2 nanotube arrays (NTAs) structure is accomplished via a pulsed electrodeposition technique. The successful preparation of this structure is owing to the high current pulse used, which creates a sufficient nucleation trend on the wall of the entire TiO2 nanotube layer, that results in the continuous deposition of MnO2 along the nanotube walls. The synthesized TiO2@MnO2 NTAs sample is found to exhibit excellent electrochemical behavior with high specific capacitance of 425.0Fg−1 and areal capacitance of 150.9mFcm−2, ranking in the top level ever achieved by a MnO2-TiO2 composite. Furthermore, a symmetric supercapacitor device is assembled using two strips of the TiO2@MnO2 NTAs electrode that yielded energy density as high as 7.4Whkg−1, a much higher value than most of the values reported for symmetric MnO2//MnO2 supercapacitors. The remarkable electrochemical properties of the TiO2@MnO2 NTAs sample make it an attractive candidate for the application of constructing high-performance supercapacitors.