Good Electron Transfer Ability Research Articles

Cu/Cu2O/C nanoparticles and MXene based composite for non-enzymatic glucose sensors

Copper/Cuprous oxide/Carbon nanoparticles decorated MXene composite was prepared and subsequently examined for its potential application as a non-enzymatic glucose sensor. To carry out this, initially the Cu MOF/MXene composite was synthesised by the hydrothermal method and was annealed in an unreacted environment at different time intervals. During this process, petal like Cu MOF on MXene loses the organic ligands to form a Cu/Cu2O/C based nanoparticles on MXene. Further, an electrode was fabricated with the developed material for understanding the sensing performance by cyclic voltammetry and chronoamperometry in 0.1 M NaOH solution. Results reveal that the highest weight percentage of copper oxide in the composite (15 min of annealed material) shows a higher electro catalytic activity for sensing glucose molecules due to more active sites with good electron transfer ability in the composite. The formed composite exhibits a wide linear range of 0.001–26.5 mM, with a sensitivity of 762.53 μAmM−1cm−2 (0.001–10.1 mM), and 397.18 μAmM−1cm−2 (11.2–26.9 mM) and the limit of detection was 0.103 μM. In addition to this, the prepared electrode shows a good reusability, repeatability, selectivity with other interferences, stability (93.65% after 30 days of storage), and feasibility of measuring glucose in real samples. This finding reveals that the metal oxide derived from MOF based nanoparticle on the MXene surface will promote the use of non-enzymatic glucose sensors.

NiS-modified zeolite imidazolic acid frame-67 as a bi-functional catalyst: A non-enzymatic lactic acid sensor and supercapacitor

The ZIF-67/NiS composite electrode was prepared on nickel foam (NF) matrix by hydrothermal method. NiS has been widely studied in sensors and supercapacitors due to its good electron transfer ability and good pseudocapacitor performance. Therefore, we prepared ZIF-67/NiS composite electrode. The synthesised ZIF-67/NiS composite electrode not only has certain electrochemical performance of battery type electrode, but also is sensitive to lactic acid (LA), and can be used as a non-enzymatic LA sensor and a dual-function material for supercapacitors. The detection limit of LA concentration in alkaline solution is 0.8 μM, and the sensitivity is 1.34 μA μM−1 cm−2. Indicating that the electrode has good electrochemical sensing performance. The GCD test results show that the charging capacity of the ZIF-67/NiS is 2.5 times that of the ZIF-67. The ZIF-67/NiS composite has good cyclic performance, and the capacitance retention rate of the ZIF-67/NiS composite is 87% at 10 A/g current density.

Impedimetric aptasensor based on MOF based composite for measuring of carcinoembryonic antigen as a tumor biomarker

In this research, gold nanoparticle (GNPs)-modified metal-organic framework/reduced graphene oxide (MOF(801)/rGO) hybrid was employed to design a new aptasensor for carcinoembryonic antigen (CEA) quantification in biological sample. The sensing ability of the electrode for CEA biomarker was examined with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry procedures. Besides, CEA was electrochemically quantified by the EIS method. With respect to the high surface–to–volume ratio of MOF(801) and the good electron transfer ability of rGO, the proposed sensor displayed notable sensitivity and reliability in the CEA analysis. The derived electrode showed an appreciable detection limit of 0.8 pg L−1 using EIS protocol. In addition, the present aptasensor revealed diverse advantages including anti-interference property, wide linear range (0.0025–0.25 ng L−1), convenience and high efficiency toward CEA quantification. More importantly, the performance of the suggested assay remains unchanged in analysis of CEA in body fluids. The established assay demonstrates that the suggested biosensor is a promising device in clinical diagnosis.

Highly Efficient Dual-Color Luminophores for Sensitive and Selective Detection of Diclazepam Based on MOF/COF Bi-Mesoporous Composites.

Currently, studies on electrochemiluminescence (ECL) mainly focused on the single emission of luminophores while those on multi-color ECL were rarely reported. Here, a bi-mesoporous composite of the metal-organic framework (MOF)/covalent-organic framework (COF) with strong and stable dual-color ECL was prepared to construct a novel ECL sensor for sensitive detecting targets. A PTCA-COF with excellent ECL performance was loaded with a great amount of another ECL emitter Cu3(HHTP)2. Remarkably, the integrated composite had both ECL properties of PTCA-COF at 520 nm and Cu3(HHTP)2 at 600 nm wavelengths. Furthermore, Cu3(HHTP)2 with good electron transfer ability can greatly enhance the electrical conductivity and promote electrochemical activation. Thus, the simultaneous enhanced two-color ECL intensity and the catalytic properties of the conductive MOF exerted a dual enhancement effect on the ECL signal of the composite. Significantly, diclazepam can not only be adsorbed well on the multi-stage porous structure MOF/COF composite by π-π interactions but also selectively quench the ECL signal of the PTCA-COF, realizing the sensitive detection. The ECL sensor showed a wide detection range from 1.0 × 10-13 to 1.0 × 10-8 g/L, and the limit of detection (LOD) was as low as 2.6 × 10-14 g/L (S/N = 3). The proposed ECL sensor preparation method was simple and sensitive, providing a new perspective for the potential application of multi-color ECL in the sensing field.

Enhancement of catalytic activity for hydrogenation of nitroaromatic by anionic metal-organic framework

Nitroaromatic hydrogenation catalysis without precious metals remains a longstanding challenge. The rate of electron transfer is the crucial factor affecting hydrogenation catalysis. Herein, an ionic Cd-based metal-organic framework (I-Cd-MOF) exhibiting a unique structure with one-dimensional (1D) opening nanochannels and good electron transfer ability was synthesized for catalyzing hydrogenation of 4-nitrophenol (4-NP). The catalytic activity of the unique I-Cd-MOF without noble metals is detected, which is higher than most reported noble metal catalysts. Remarkably, the reaction rate of I-Cd-MOF (4.28 min−1) is about 47.6 times higher than that of the Cd-based neutral MOF (N-Cd-MOF) with the similar crystalline structure. Liquid chromatograph mass spectrometer (LC-MS) and theoretical results demonstrate that 4-NP and five intermediates are stabilized in the channels of I-Cd-MOF, which increases the possibility of contact with H* and H2 generated at the Cd sites. The I-Cd-MOF was extended to other nitroaromatic hydrogenation catalysis, which still displays excellent activity. More importantly, the I-MOF@Filter membrane was successfully constructed for continuous hydrogenation catalytic reactions, which maintains a high catalytic performance after 7 cycles of recycling without washing. This work fills in the application of the I-MOFs in hydrogenation catalytic reactions and provides an effective way for the rapid and green degradation of nitroaromatic compounds.

Efficient Oxygen Vacancy Defect Engineering for Enhancing Visible-Light Photocatalytic Performance over SnO2-x Ultrafine Nanocrystals.

Regardless of its good electron-transfer ability and chemical stability, pure Zn2SnO4 (ZSO) still has intrinsic deficiencies of a narrow spectral response region, poor absorption ability, and high photo-activated carrier recombination rate. Aiming to overcome the deficiencies above-mentioned, we designed a facile hydrothermal route for etching ZSO nanoparticles in a dilute acetic acid solution, through which efficient oxygen vacancy defect engineering was accomplished and SnO2−x nanocrystals were obtained with an ultrafine particle size. In comparison with the untreated ZSO nanoparticles, the specific surface area of SnO2−x nanocrystals was substantially enlarged, subsequently leading to the notable augmentation of active sites for the photo-degradation reaction. Aside from the above, it is worth noting that SnO2−x nanocrystals were endowed with a broad spectral response, enhancing light absorption capacity and the photo-activated carrier transfer rate with the aid of oxygen vacancy defect engineering. Accordingly, SnO2−x nanocrystals exhibited significantly enhanced photoactivity toward the degradation of the organic dye rhodamine B (RhB), which could be imputed to the synergistic effect of increasing active sites, intensified visible-light harvesting, and the separation rate of the photo-activated charge carrier caused by the oxygen vacancy defect engineering. In addition, these findings will inspire us to open up a novel pathway to design and prepare oxide compound photocatalysts modified by oxygen vacancy defects in pursuing excellent visible-light photoactivity.

Electrochemical determination of hydrazine by using MoS2 nanostructure modified gold electrode

In this paper, MoS2 nanostructure was synthesized by using ammonium molybdate and thiourea as precursors through annealing in a tube furnace. The nanostructure was characterized for morphological, structural and elemental composition by using a field emission scanning electron microscope (FESEM), powder X-ray diffraction and energy-dispersive X-ray spectroscopy (EDS). The as-synthesized nanostructure was then immobilized on the gold electrode (working electrode) for the electrochemical detection of hydrazine. Cyclic voltammogram shows an intense peak at 22 µA, which proved the high electrocatalytic ability of the sensor. The strong electrocatalytic activity regarding the oxidation of hydrazine is ascribed to good electron transfer ability and high surface area of the nanoparticles. Further, the chronoamperometric study was conducted to estimate the sensitivity and the detection limit of the sensor. The sensor exhibited a detection limit and sensitivity of 196 nM and 5.71 µA/µM cm2 respectively. Promising results such as high electrical conductivity, lower detection limit and high sensitivity of the as-synthesized MoS2 nanostructure have proved its potential towards the electrochemical detection of hydrazine.

Aptamer-Adjusted Carbon Dot Catalysis-Silver Nanosol SERS Spectrometry for Bisphenol A Detection.

Carbon dots (CDs) can be prepared from various organic (abundant) compounds that are rich in surfaces with –OH, –COOH, and –NH2 groups. Therefore, CDs exhibit good biocompatibility and electron transfer ability, allowing flexible surface modification and accelerated electron transfer during catalysis. Herein, CDs were prepared using a hydrothermal method with fructose, saccharose, and citric acid as C sources and urea as an N dopant. The as-prepared CDs were used to catalyze AgNO3–trisodium citrate (TSC) to produce Ag nanoparticles (AgNPs). The surface-enhanced Raman scattering (SERS) intensity increased with the increasing CDs concentration with Victoria blue B (VBB) as a signal molecule. The CDs exhibited a strong catalytic activity, with the highest activity shown by fructose-based CDs. After N doping, catalytic performance improved; with the passivation of a wrapped aptamer, the electron transfer was effectively disrupted (retarded). This resulted in the inhibition of the reaction and a decrease in the SERS intensity. When bisphenol A (BPA) was added, it specifically bound to the aptamer and CDs were released, recovering catalytical activity. The SERS intensity increased with BPA over the concentration range of 0.33–66.67 nmol/L. Thus, the aptamer-adjusted nanocatalytic SERS method can be applied for BPA detection.

Copper selenides controlled hydrothermal synthesis of porous micro-networks with highly efficient photocatalysis

Hybrid photocatalysts have important prospects in clean energy and sewage treatment. Herein, we construct functional hybrid materials consisting of nonstoichiometric copper selenides (Cu2-xSe) and porous gadolinium micro-networks (P-MNs) formed by the hydrothermal treatment of gadolinium (III) nitrate and citric acid (Cu2-xSe/P-MNs) as the excellent photocatalyst for the photodegradation of fluorescent dyes. Cu2-xSe/P-MNs photocatalysts show good chemical stability because the hybridization of Cu2-xSe and P-MNs is based on an in-situ growth strategy. More importantly, due to the strong light-harvesting and good electron transfer ability, Cu2-xSe/P-MNs show superior photocatalytic activity with a catalytic rate of up to 0.33 min−1 only under the irradiation of 20 W of low-power white light, which is at least two orders of magnitude higher than other common photocatalysts. Detailed studies show that the h+, O2•−, and ⋅OH are the main active species in the photocatalytic process. According to the ‘three channel’ catalytic path, rhodamine 6G as the model dye can be completely and rapidly degraded within 15 min. Because of the good photocatalytic activity, Cu2-xSe/P-MNs show great application prospects.

A Review of the Application of Heterostructure Catalysts in Hydrogen Evolution Reaction

AbstractHydrogen energy as a significant part of clean energy in the future has been widely studied. Hydrogen production from electric cracking water is the most effective and mature development method at present. Heterostructured electrocatalysts are favored due to their low overpotential, excellent assembly structure and good electron transfer ability. Consequently this paper reviews the development of heterogeneous electrocatalysts, the measurement parameters of electrocatalytic hydrogen evolution reaction (HER), and related research progress, and gives the hydrogen evolution mechanism in acidic, alkaline and neutral environments. Finally, we explain the essential development direction and severe challenges in this field.

A β-nicotinamide adenine dinucleotide electrochemical sensor based on polyoxometalate built by the combination of electrodeposition and self-assembly

• A NADH sensor was developed by electrodeposition combining the LbL method. • The current of NADH was greatly improved by this sensor. • The sensor exhibited wide linear range, low detection limit and high selectivity. • The combination of electrodeposition and LbL provided strong stability of sensor. β-nicotinamide adenine dinucleotide (NADH), as vital coenzyme involved, is expected to be accurately detected in Clinical diagnosis and treatment. Polyoxometalates (POMs) have unique redox capacity with good electrochemical reversibility and fast electron transfer ability, which makes them become favorite materials for sensors. Here by using alternating electrodeposition and self-assembly techniques, Keggin-type polyoxometalates (PMo 11 V) were modified on glassy carbon electrodes with the help of polyallylamine hydrochloride (PAH), to construct a sensitive and stable electrochemical sensor for detection of NADH. The proposed (PAH/PMo 11 V) 4 /GCE was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV) measurements and amperometrics method (i-t). The obtained electrode has high stability, good reproducibility, outstanding sensing capability for NADH, with a low detection limit of 1.9 × 10 -8 M, a wide linear range from 3.2 × 10 -7 to 8.2 × 10 -5 M and 1.1 × 10 -5 to 1.01 × 10 -3 M. This strategy, overcoming the drawbacks of POMs and solving the shortcomings that NADH requires high electrocatalytic potential, is simple in operation, low in cost, and could be widely used in electrochemisty field.

Efficient Visible-Light-Responsive Ag3PO4/g-C3N4/Hydroxyapatite Photocatalyst (from Oyster Shells) for the Degradation of Methylene Blue: Preparation, Properties and Mechanism

A novel ternary Ag3PO4/g-C3N4/hydroxyapatite photocatalyst was prepared, and its morphology, composition and structure were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and electron spin resonance, etc. The results show that g-C3N4 is evenly dispersed in the interior of hydroxyapatite, forming a homogeneous composite, and significantly improves the band gap structure of the material as a whole. Ag3PO4/g-C3N4/hydroxyapatite has good electron transfer ability and an appropriate energy band structure, which shows that the material has a good degradation effect and stability. Finally, based on the characterization and experimental results, a possible Z-scheme mechanism was proposed, and the active species involved in the reaction are mainly ·O2− and h+.

Ultrasensitive sandwich RNA-aptasensor based on dual-signal amplification strategy for highly sensitive neomycin detection

This study aimed to design a highly sensitive electrochemical aptasensor based on the dual-signal amplification strategy for detecting neomycin (NEO) in milk samples. The electronic signal of multi-walled carbon nanotubes (MWCNTs) was greatly improved due to the existence of ferrocene (Fc), which had good electron transfer ability. The silica hybridized mesoporous ferroferric oxide nanoparticles (Fe3O4@SiO2) were prepared by hydrothermal and chemical activation treatments, which had a large specific pore volume and a large specific surface area, they could fix more RNA aptamers (Apts) and promote the electron transfer of nanoparticle labels. A composite sandwich was formed between the two Apts (Apt1 and Apt2) and the target. Also, Apt2 was modified by gold nanoparticles (AuNPs), enhancing the electrochemical signal. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to characterize the performance of the aptasensor in detail. Under optimized conditions, the response current differences of the electrochemical aptasensor exhibited a linear relationship toward the positive logarithm of NEO concentrations ranging from 5 × 10−3 nM to 5 × 102 nM and a detection limit of 0.759 nM. The electrochemical aptasensor showed specificity and selectivity. In addition, the constructed aptasensor was successfully applied to the detection of NEO in milk. These results indicated that the aptasensor had potential applications in the actual monitoring of NEO.

Ni2P/biocarbon composite derived from an unusual phosphorus-rich precursor as a superior catalyst for 4-nitrophenol reduction

Conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) through advanced reduction process is important to lower the hazardous risk of 4-NP, which requires the development of highly efficient catalyst. Herein, we proposed a novel strategy to fabricate nickel phosphide/carbon composite for 4-NP reduction in the presence of NaBH4. An unusual precursor of adenosine 5′-triphosphate (ATP) was applied to provide the essential phosphorus and carbon elements for nickel phosphide and biocarbon, respectively. ATP-Ni complex was firstly prepared and then transformed to nickel phosphide/biocarbon composite by an anoxic pyrolysis treatment. Material characterizations confirmed both large particles of hundreds of nanometers and small particles of ∼2.4 nm existing for Ni2P, which were dispersed on N/P-doped biocarbon with thin layer sheet-like structure. When applied for 4-NP reduction, Ni2P/BC exhibited fast reaction kinetic with a pseudo-first-order reaction rate constant of 0.019 s−1 (normalized rate constant 253 s−1 g−1) and good reusability in 10 consecutive reaction runs (95.8% conversion efficiency). It is suggested that such superior activity may originate from the high affinity of Ni2P/BC towards reactants and the good electron transfer ability of Ni2P/BC. This study not only enriches the synthesis strategy of transition metal phosphide, but also provides a superior catalyst for advanced reduction process.

Enhanced solar photocatalytic degradation of nitric oxide using graphene quantum dots/bismuth tungstate composite catalysts

• A novel method for the preparation of graphene quantum dots/bismuth tungstate (GQDs/BWO) composite photocatalysts. • Performance evaluation of enhanced sunlight responsive photocatalytic performance of GQDs/BWO composite for nitric oxide degradation. • The formation of Z-scheme heterojunction between GQDs and Bi 2 WO 6 . • The mechanism of photocatalysis of the GQDs/BWO photocatalysts. Composite (GQDs/BWO) materials for enhanced photocatalysis are hydrothermally produced by combining graphene quantum dots (GQDs) with bismuth tungstate (Bi 2 WO 6 ). These GQDs/BWO nanomaterials are evaluated for photocatalysis, at different GQDs loadings, for the degradation of gaseous nitric oxide with concentrations of 10–11 ppm. Results show that 10GQDs/BWO has the best photocatalytic performance among competitors for NO degradation. The NO conversion rate reaches 73% during 30 min, which is 3.84 times higher than that of pure Bi 2 WO 6 . This is because GQDs not only have a good electron transfer ability, but also form a direct Z-scheme heterojunction with Bi 2 WO 6 . These features promote electron-hole separation efficiency of the composite catalyst, and inhibit their recombination. This performance results from the increase in the surface area of the composite and to the increase in light absorption. The selectivity for the formation of NO x - ( S N O x - ) increased from 66 to 88%, and the DeNO x index increased from −0.003 to 0.43 after the introduction of GQDs. Active species scavenger experiment, Mott-Schottky (MS) tests and density functional theory (DFT) calculations are used to evaluate the mechanism of photocatalytic NO. Furthermore, cyclic tests show that 10GQDs/BWO catalysts maintain their chemical stability for NO degradation over 8000s.

Azo-linked covalent triazine-based framework as organic cathodes for ultrastable capacitor-type lithium-ion batteries

A highly stable 3D π-conjugation covalent triazine-cored framework (Azo-CTF) with triazine as the electron-rich center bridged by azo redox-active linkers is proposed and prepared as cathode materials for improving both rate performance and cycle stability of LIBs, two critical issues addressed in organic electrodes. The synchronous and orderly introduction of electron-withdrawing units and redox active units in conjugated polymer framework can effectively tune electronic structure and redox potential of materials, contributing to the improvement of electrical and electrochemical behavior. Attributed to abundant redox azo sites, resilient and accessible pores network, and good intramolecular and interfacial electron transfer ability, Azo-CTF cathode shows a large and reversible capacity output of 205.6 mAh g−1, a ultralong cycle life (89.1% capacity retention after 5000 cycles), and a high power density of 4253 W kg−1 even at an energy density of 258 Wh kg−1, much better than many reported organic cathodes and even better than some commercial inorganic cathodes. In addition, in-situ Raman spectroscopy and theoretical calculations were done and further verified the redox process of azo active sites and the optimization of molecular orbital in covalent framework for better battery cathode, indicating the availability of molecular-level electronic structure tuning.

Electrochemical immunosensor for serum parathyroid hormone using voltammetric techniques and a portable simulator

An electrochemical platform based on a screen-printed carbon electrode (SPCE) is developed to detect parathyroid hormone (PTH). A nanocomposite of multi-walled carbon nanotube (MWCNT) and gold nanoparticles (AuNP) was deposited on the SPCE to immobilize antibodies and horseradish peroxidase (HRP). MWCNT improved the stability and conductivity of the immunosensor because of its good electron-transfer ability and tubular structure. The AuNP not only provided a large surface area for antibody immobilization, but it also enhanced the electrochemical signal for enzyme-linked immunosensing. Cyclic voltammetry showed both electron transfer and the effective surface area were increased on the modified electrode. The characteristics of the modified SPCE were assayed by Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and electrochemical techniques. The linear detection range of this PTH immunosensor was within 1–300 pg/ml, and the electrochemical performance was not affected by interference from protein components in human serum. After storage at 4 °C for 28 days, 85% PTH sensing ability of this immunosensor was maintained compared to the freshly prepared one using the SWV and DPV methods. The relative standard deviations of all measurements were within 3–8% for both voltammetric methods. These results indicated the developed immunosensor had good stability and reproducibility. This PTH immunosensor had a detection limit of 0.886 and 0.065 pg/ml for the differential pulse voltammetry and square wave voltammetry, respectively. We provided a quick analysis of serum PTH which might be used as an electrochemical immunosensing platform for point-of-care testing.

Photoreactivity study of photoinitiated free radical polymerization using Type II photoinitiator containing thioxanthone initiator as a hydrogen acceptor and various amine-type co-initiators as hydrogen donors

In this work, free radical photopolymerization of trimethylolpropane trimethacrylate (TMPTMA) is initiated. We investigated the corresponding photoreactivity by using Type II photoinitiator (PI) systems based on thioxanthone (TX) as a hydrogen acceptor and five amine-type molecules, such as N-phenylglycine (NPG), triethylamine (TEA), triethanolamine (TEOA), 2,2′-(4-methylphenylimino)diethanol (p-TDEA), and N-phenyldiethanolamine (n-PDEA), as hydrogen donors. Their photochemical and photophysical properties are studied. The TX hydrogen acceptor displayed rather red-shifted compared to all the hydrogen donor compounds. The hydrogen donor compounds exhibited the absorption band at lower than 300 nm, which followed the trend of p-TDEA > n-PDEA > NPG > TEOA > TEA. All the packages exhibit good electron-transfer ability by the calculation of the free energy changes (ΔGET) through cyclic voltammetry (CV) measurement. However, the hydrogen donors with different steric hindrance, secondary, and tertiary amines have a decisive influence on the photoreactivity; that is, the TX/TEOA package shows the best double-bond conversion (DC) efficiency than other formulations under similar weight ratios (hydrogen acceptor: hydrogen donor = 1:2 wt%). We then conduct the photoreactivity based on TX/TEOA formulation with different weight ratios. The DC values are in the order of 1:2 wt% > 1.5:1.5 wt% > 2:1 wt%. Under suitable amount of hydrogen donor, the TX/TEOA-based formulation also exhibits stable DC value at air atmosphere.

High visible light response Z-scheme Ag3PO4 / g-C3N4 / ZnO composite photocatalyst for efficient degradation of tetracycline hydrochloride: Preparation, properties and mechanism

Abstract A novel ternary Z-scheme Ag3PO4/g-C3N4/ZnO photocatalyst has been prepared and was characterized by XRD, FTIR, XPS, SEM and TEM, UV–Vis DRS, Transient fluorescence spectra and EIS Nyquist plots to describe the morphology, structure and photocatalytic performance. The result of the characterization shows that the three substances successfully formed a composite Ag3PO4/g-C3N4/ZnO which exhibits enhanced performance and stability, due to the good electron transfer ability and suitable band structure. The degradation rate of tetracycline hydrochloride can reach 88.48% under the best conditions and more sensitive to sunlight. After using four times, the Ag3PO4/g-C3N4/ZnO still shows good degradation efficiency, indicating advanced photocatalytic properties and improved stability. Finally, a possible Z-scheme mechanism is proposed on the basis of the results of characterization and degradation experiments, showing that ZnO performs as electronic conductor between Ag3PO4 and g-C3N4, while Ag3PO4 and g-C3N4 generate h+ and •O2−. The resulting formation of Z-scheme structure showed decreased photocorrosion and improved stability.

Synthesis of CNTs on ZnO/NiS composite as an advanced electrode material for high-performance supercapacitors

The design and preparation of an efficient electrode material with a multifunctional surface structure is a key challenge for high-performance supercapacitors. In this study, ZnO/NiS and ZnO/NiS/CNT nanocomposites were synthesized on a nickel foam substrate and used as an electrode material. The surface morphology and structure of the electrodes were analyzed by field emission–scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The prepared nanocomposite of ZnO/NiS/CNT exhibited a high specific capacitance of 879.0 F g−1 at a current density of 1.5 A g−1, along with remarkable cycling stability of 89.7% capacitance retention after 5000 cycles, which was superior to that of ZnO/NiS (805.75 F g−1 and 74.59% retention). In addition, the ZnO/NiS/CNT electrode also exhibited good rate capability, faster ion and electron transfer ability, and higher surface area, highlighting its potential for electrochemical energy storage.