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Electrocatalysts for hydrogen evolution made from earth’s rich elements are key to a sustainable and clean hydrogen economy. Now, using a straightforward way to make valid catalysts with preferable catalytic activity from inexpensive raw materials in large scale remains challenge. The preparation of nickel-sulfur hybrid nanoplate electrocatalyst has a deep consideration because of its ordinary preparation process, outstanding property, and fine stabilization. In this work, employing an improved chemical vapor deposition (CVD) synthesis method to fabricate a highly efficient and stable NiS2/NiS electrocatalyst prepared by changing the mass of nickel-sulfur ratios of 8:1 (NiS2/NiS-8), 4:1 (NiS2/NiS-4), 2:1 (NiS2/NiS-2), and 1:1 (NiS2/NiS-1), applied to hydrogen evolution reactions (HER). The acquired NiS2/NiS-4 showed excellent HER performance with an overpotential of 202 mV to drive 100 mA/cm2 in 1 M KOH solution with a Tafel slope of 69.0 mV/dec, also with 30 h stability testing. This vigorous catalyst, fabricated from commercial Ni foam, has a potential for industrialization of hydrogen economy and will stimulate the industrial development of nonprecious metal catalyst.

The emergence of alternative sustainable energy technologies has stimulated the utilisation of high-efficiency, cost-effective electrodes for renewable energy conversion. The oxygen evolution reaction (OER) is critical for water splitting and rechargeable metal-air batteries. However, the identification of efficient and robust non-noble-metal-based OER electrocatalysts remains a major hurdle for large-scale hydrogen production. Herein, NiVP@NiFeV-LDH heterojunction catalysts were constructed by phosphidation and hydrothermal processing, because OER activity can be improved by coupling NiVP and NiFeV-LDH. NiVP@NiFeV-LDH/NF exhibited remarkable OER performance with an ultralow overpotential of 317 mV at a current density of 100 mA cm−2 and a Tafel slope of 83.0 mV dec−1 in an alkaline environment. The high efficiency of NiVP@NiFeV-LDH/NF is attributed to increased mass and electron transport because of array structure formation and interfacial electronic structure optimisation, respectively. This work provides a novel approach for augmenting the OER performance of non-noble-metal-based electrocatalysts for energy conversion applications.

The oxygen evolution reaction (OER) involves four electron transfer processes and is of great significance in water electrolysis. The development of efficient and robust non-precious OER electrocatalysts remains a critical challenge for the production, storage and conversion of renewable energy. Herein, vertically NiCo2O4 nanosheets are grown on Ti mesh via a facile solvothermal method which is followed by low-temperature calcination. The NiCo2O4/Ti catalyst exhibits outstanding OER performance with a low overpotential of 353 mV to drive the current density of 10 mA cm−2 and a Tafel slope of 61 mV dec−1 in alkaline solution. Moreover, the stable electrocatalyst undergoes negligible degradation in alkaline media at least 20 h. The acceleration of the electrochemical OER likely stems from the facile electron transfer promoted by the NiCo2O4/Ti interface as revealed by X-ray photoelectron spectroscopy. This work introduces a novel strategy for the establishment low-cost electrocatalysts for electrochemical water splitting.

Ammonium vanadate (NH4V3O8) materials have attracted considerable attention due to their low cost, high discharge capacity, and simple synthesis process. However, the further application of NH4V3O8 materials as cathode for lithium-ion batteries is hindered by the low electronic conductivity and lithium-ion diffusion coefficient. Herein, intersperse Super P nanoparticles between NH4V3O8 microsheets to increase the Li+ diffusion coefficient of NH4V3O8 electrodes. Compared with pure NH4V3O8, the cycling stability of NH4V3O8/Super P composites improved obviously. At a current density of 15 mA g−1 after 200 cycles, the reversible capacity of composites (110 mAh g−1) is much higher than the pure NH4V3O8 (70 mAh g−1). Besides, the composites exhibit excellent rate capability, and the reversible capacity achieves 66 mAh g−1 at a high current density of 300 mA g−1. The excellent electrochemical performance is mainly attributed to the addition of Super P carbon black nanoparticles, which increases the conductivity and the Li+ diffusion coefficient.

A hybrid heterostructure eletrocatalyst supported on Ni foam is facilely synthesized as a high-performance OER electrocatalyst for alkaline water electrolysis. Compared to their pristine NiV-LDH counterpart, the self-made NiV-LDH@FeOOH heterostructures exhibit an extremely low overpotential of ∼297 mV at 100 mA cm-2 current output, and excellent long-term durability.

Recent research on organic semiconductors has revealed that the composition of the constituent organic material, as well as the subtle changes in its structure (the stacking order of molecules), can noticeably affect its bulk properties. One of the reasons for this is that the charge transport in conjugated materials is strongly affected by their structure. Further, the charge mobility increases significantly when the conjugated materials exhibit self-assembly, resulting in the formation of ordered structures. However, well-organized nanostructures are difficult to obtain using classical solution processing methods, owing to their disordered state. A simple strategy for obtaining well-ordered material films involves synthesizing new conjugated materials that can self-organize. Introducing hydrogen bonding in the materials to yield hydrogen-bonded material superstructures can be a suitable method to fulfill these critical requirements. The formed hydrogen bonds will facilitate the assembly of the molecules into a highly ordered structure and bridge the distance between the adjacent molecules, thus enhancing the intermolecular charge transfer. In this minireview, hydrogen-bonded small molecules and polymers as well as the relationship between their chemical structures and performances in organic field-effect transistors are discussed.

Ag-doped ZnO nanorods growth on a PET-graphene substrate (Ag-ZnO/PET-GR) with different Ag-doped content were synthesized by low-temperature ion-sputtering-assisted hydrothermal synthesis method. The phase composition, morphologies of ZnO, and electrical properties were analyzed. Ag-doping affects the initially perpendicular growth of ZnO nanorods, resulting in oblique growth of ZnO nanorods becoming more obvious as the Ag-doped content increases, and the diameter of the nanorods decreasing gradually. The width of the forbidden band gap of the ZnO films decreases with increasing Ag-doped content. For the Ag-ZnO/PET-GR composite structure, the Ag-ZnO thin film with 5% Ag-doped content has the largest carrier concentration (8.1 × 1018 cm−3), the highest mobility (67 cm2 · V−1 · s−1), a small resistivity (0.09 Ω·cm), and impressive electrical properties.

Three π-conjugated large organic molecules based on diketopyrrolopyrrole (DPP), benzodipyrrolidone (BDP) and naphthodipyrrolidone (NDP) are synthesized and characterized. By introducing bi-thiophene units at the end of DPP/BDP/NDP chromophores, the molecules are able to form a donor–acceptor–donor (D-A-D) system. All of them exhibit high thermal stability, strong aggregation, high values in highest occupied and low values in lowest unoccupied molecular orbital (HOMO/LUMO) energy levels. In this work, a simple solution process technique for large organic molecules crystal organic field-effect transistors (OFETs) is used to fabricate devices. DPP- and BDP-based large organic molecular crystals exhibit p-type behavior with hole mobility of 0.02 cm2 V−1 s−1 and 0.09 cm2 V−1 s−1, while large organic molecular crystal based on NDP shows n-type behavior with electron mobility up to 0.26 cm2 V−1 s−1. This work demonstrated that extension of the π-conjugation system is a useful strategy to build high charge mobility materials. In addition, BDP is an interesting electron-withdrawing block for p-type semiconductor while NDP is a promising chromophore for the construction of n-type high-performance OFETs.

The water oxidation reaction plays a major role in many alternative-energy systems because it provides the electrons and protons required for the use of renewable electricity. We report the tuning of the iron molybdate (FeMoO4) electron structure via a coupled interface between the catalytic centers and the substrate. Our developed FeMoO4 catalysts can provide a 50 mA cm-2 current density at 1.506 V vs. RHE with excellent stability in 1.0 M KOH. The improved performance can be ascribed to the synergy of the optimized electronic structures and hierarchical nanostructure.

A novel donor-acceptor type aminobenzodifuranone based chromophore molecule, coded as ABDF, with a benzodifuranone (BDF) core as acceptor and an N-ethylamino side chain as donor moiety was synthesized and used in single crystal organic field-effect transistors (OFETs). The optical, thermal, electrochemical properties of ABDF were also investigated. Compared to other BDF or halogenated BDF analogs, the solution absorption of ABDF exhibits large bathochromic shift over 100 nm, indicating the strong intramolecular charge transfer intensity within the molecules. In particular, the incorporation of amino groups into the BDF core also enables the formation of intermolecular hydrogen-bonding interactions in the solid states of ABDF as proved by the FT-IR results. The crystalline ABDF based OFET devices was simply prepared by drop-casting the ABDF solution on to the electrode-prepatterned substrates, giving a hole mobility as high as 0.42 cm2/V·s without large degradation after store in ambient environment for up to two months. ABDF is a promising chromophore for high performance organic field-effect transistors.

The exploration of high-performance, inexpensive noble-metal-free electrocatalysts for the oxygen evolution reaction (OER) may be critical for sustainable mass production of renewable energy. In this study, vanadium-doped Ni3S2 nanorod arrays grown on three-dimensional nickel foam (V-Ni3S2/NF) were designed and synthesized by a facile hydrothermal route. Electrochemical measurements showed that the sample with an appropriate amount of V doping (S: V mass ratio of 25:3) exhibited superior OER performance, with an overpotential of 189 mV at a current density of 100 mA cm−2 and a low Tafel slope of 148.87 mV dec−1. The improved catalytic performance can be attributed to the optimization of the electronic structure resulting from enhanced electron transfer due to doping with impurity atoms. Detailed characterization showed that homogeneous V doping changed the morphology of Ni3S2 from nanosheets to nanorods; it also introduced additional catalytic active sites and significantly improved the electrocatalytic activity for the OER. In addition, V-Ni3S2/NF exhibited excellent electrocatalytic stability compared to noble-metal (IrO2) electrocatalysts. The introduction of vanadium suggests a new approach to the design of high-performance OER catalysts in alkaline medium.

Electrochemical oxidation of biomass convert into worthy production is considered to be a prospective alternative to slow kinetic oxygen evolution reaction (OER) in order to facilitate H2 generation. Herein, Mo-doped Ni0.85Se on the Ni foam (denoted as NF@Mo-Ni0.85Se) was prepared as effective bifunctional catalyst to boost H2 production and translate 5-hydroxymethylfurfural (HMF) into 2, 5-furfuran carboxylic acid (FDCA) simultaneously. Operando electrochemical impedance spectroscopy (EIS) and theoretical calculations confirm that the Mo doping could speed the electron transmission within the catalyst and downshift the d-band center of Ni in NF@Ni0.85Se, which is not only conducive to abating H* adsorption energy, but further promotes the hydrogen evolution reaction (HER) and organic hydrogen adsorption process. The as-synthesized electrocatalysts have shown outstanding hydrogen evolution property in acid, neutral, alkaline and seawater. When the NF@Mo-Ni0.85Se||NF@Mo-Ni0.85Se catalyst couple was employed for HER as well as HMF oxidation in basic electrolytes, the potential only required a potential of 1.50 V to obtain the current density of 50 mA cm−2, lower than that of overall water splitting (1.68 V). This present work especially emphasizes the significance of doping transition metals to improve material properties for constructing bifunctional electrocatalysts towards highly efficient energy utilization.

Hollow core@shell TiO2@CdS composite was synthesized via facile and controlled homogeneous precipitation method, the as-prepared samples were characterized by XRD, SEM, TEM, FTIR, EDS UV–vis adsorption, and BJH. The results of the photocatalytic experiment demonstrated the TiO2/CdS hybrid with Ti/Cd molar ratio of 1:2 (denoted as T/2C) possesses the highest photocatalytic activity, the degradation rate of T/2C towards methyl orange (MO) is 78% and 80% under simulated UV light and sun light, respectively. Additionally, T/2C also presents photocatalytic performance on H2 production (114.375 µmol/h g). Based on the experiment results, a probable charger transfer mechanism of T/2C was proposed. In view of the unique hollow structure and high photocatalytic characteristics, it is looking forward to exhibit great potential for applications in wastewater treatment and H2 evolution.

Nanocoating combine the protective properties of conventional coating system with effects on nanoscale such as high hardness, UV scattering, uniform dispersing, etc. Their facile and low-cost synthesis, together with superior protective properties and multi-functionalities, makes nanocoating attractive candidates for next-generation coating system. In this review, a brief introduction regarding to mainstream nanocoating and its related challenges including the zinc oxide-, titanium dioxide-, silica dioxide-, graphene-, carbon nanotube-based nanocoating system is presented. Finally, a perspective of the nanocoating is demonstrated.

In this work, a series of near-infrared reflective inorganic pigments with a general formula Co0.5Mg0.5Al2 − xFexO4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were successfully prepared by Pechini-type sol–gel method. Comprehensive analyses were carried out to characterize the developed pigment powders including thermogravimetry and differential scanning calorimetry, X-ray diffraction, field emission scanning electron microscopy, ultraviolet–visible near infrared diffuse reflectance spectroscopy, and CIE-L⁎a⁎b⁎ 1976 color scales. The results demonstrated that the single-phase Co0.5Mg0.5Al2 − xFexO4 was synthesized at an optimum temperature of 900 °C. The resulting calcined powders have a well-developed cubic spinel structure. The substitution of Fe3 + for Al3 + in Co0.5Mg0.5Al2 − xFexO4 changes the color from blue to black and the band gap shifts from 4.40 eV to 3.50 eV. And Fe doped pigments possess high near-infrared solar reflectance (> 43%) in the range of 780–2500 nm. Therefore, these Co0.5Mg0.5Al2 − xFexO4 powders have great potential in serving as cool pigments for building coatings.

Wheat straw (WS), as a cheap and abundant agricultural waste, is usually burned directly in farmland and causes severe air pollution. Therefore, biochar derived from waste WS is prepared and modified by nanoscaled zinc oxide through a facile in-situ surface-modification process. For ease of use, a 3D printed finger-sized unit (FSU) loaded with the above as-prepared WS is designed and implemented. Each unit weighs only 4 g, and could simultaneously reduce three major water contaminants: bacteria, organic dyes, and heavy metal ions. Moreover, it is interesting to note that fresh wheat straw is a flexible material and has excellent electrical conductivity after carbonization. These two properties (flexibility and conductivity) could further adjust water purification performance. The subsequent cellular and animal tests confirmed the biosafety of the water purified with FSU alone.

In this study, the hydrophobic alumina aerogels were successfully prepared using oil shale ash (OSA) as a new raw material. The process consisted of two stages, leaching of aluminum and hydrophobic modification. The effects of methyltrimethoxysilane (MTMS) and tetraethylorthosilicate (TEOS) used as surface modifying agents on the physicochemical properties of the alumina aerogels were investigated. The surface chemical group, thermal stability, structure properties and morphological features before and after modification were examined by Fourier transform infrared (FT-IR), Thermogravimetry–differential thermal analysis (TG–DTA), Brunauer–Emmett–Teller (BET) and Scanning electron microscope (SEM) techniques. The experimental results indicated that the obtained alumina aerogels without surface modification had ordered mesoporous structure and flaky morphology with average length of about 200–300 nm. After surface modified with MTMS, the surface property of alumina aerogels changed from hydrophilic to hydrophobic, meanwhile the morphology changed to catkin-like structure. The results obtained in this experiment prove that the OSA can be used to prepare hydrophobic alumina aerogels, which explores a new way for comprehensive utilization of OSA.

a b s t r a c t A simple impedimetric immunosensor was developed for ultrasensitive detection of interleukin-6 (IL-6) antigen. The sensing platform integrated two substrates that had previously been employed individually to detect IL-6. This was constructed by electrochemically depositing Au nanoparticles on horizontally aligned single walled carbon nanotube array that has been in situ prepared on a SiO2/Si substrate. The as-prepared immunosensor was able to detect IL-6 antigen in serum at a low limit of 0.01 fg mL −1 , which was greatly lower than the detection limit reported with carbon nanotube forest or Au nanoparticles alone and was also significantly lower than that seen in a healthy individual. The sensor has a wide linear response range from 0.01 to 100 fg mL−1 and also exhibits low responses to a number of interferents that were found in serum. The sensor has a high stability and its sensitivity does not change after being stored at 4 ◦ C for a month.

Eu 3+ and Tb 3+ co-doped NaLa(MoO 4 ) 2 phosphors with various shapes have been synthesized by a simple conventional hydrothermal method. The morphology of the materials was found to be manipulated by changing the pH value of the precursor hydrothermal media. Uniform NaLa(MoO 4 ) 2 3D microspheres could be trapped at pH 5 and the spindle-like NaLa(MoO 4 ) 2 microstructures were obtained at pH 7. When the pH value was adjusted to 9, the flower-like NaLa(MoO 4 ) 2 microstructures were obtained. The luminescent properties of the NaLa(MoO 4 ) 2 :Eu 3+ /Tb 3+ samples with different morphologies prepared at different starting pH values were studied. The results show that the emission intensity of the product obtained at pH 5 is the strongest. Besides, under ultraviolet excitation the luminescence colors of NaLa(MoO 4 ) 2 samples co-doped with Eu 3+ and Tb 3+ can be tuned from red, through yellow and green–yellow, to green by simply adjusting the relative doping concentrations of the activator ions. This merit of multicolor emissions in the visible region endows the as-prepared products with potential application in the fields of light-display systems and optoelectronic devices.

Uniform YF 3 nanocrystals were prepared through a facile ethylene glycol (EG)/ionic liquid interfacial synthesis route in a imidazolium ionic liquids (1-octyl-3-methylimidazolium hexafluorophosphate) with the ionic liquids acting as both reagents and templates. The partial hydrolysis of PF 6 − was utilized to introduce a fluoride source. X-ray diffraction (XRD), field emission scanning microscopy (FE-SEM) and transmission electron microscopy (TEM) have been used to study the morphologies and crystal structure. The detailed growth mechanism of the YF 3 nanocrystals was researched. Furthermore, under ultraviolet exaltation, the phosphor of YF 3 :Eu 3+ and YF 3 :Tb 3+ shows red and green emission, corresponding to 5 D 0 – 7 F 1 transition of Eu 3+ and 5 D 4 – 7 F 5 transition of Tb 3+ . The emission spectrum of YF 3 :Ce 3+ phosphor exhibits one dissymmetrical band extending from 350 to 500 nm with a maximum at about 383 nm. A bright fluorescent yellow emission at 574 nm and blue emission at 487 nm were observed in the YF 3 :Dy 3+ . These novel nanocrystals could be potentially used in biolabels and light emitting diodes (LEDs).

This study investigated electrochemical detection of human hepatitis B and papilloma viruses using electrochemical impedance spectroscopy technique. The sensor was fabricated by electrochemically depositing Au nanoparticles on the in situ prepared single walled carbon nanotube (SWCNTs) arrays, followed by the self-assembly of single-stranded probe DNA on the SWCNTs/Au platform. The as-prepared electrochemical sensor could detect lower than 1 attomole complimentary hepatitis B single-stranded DNA (ssDNA), which corresponds to having 600 ssDNA molecules in a 1.0 mL sample. For a 1-base mismatched hepatitis B ssDNA, the experimental detection limit is 0.1 pmol. When being applied to detect 24-base papilloma virus ssDNA, the experimentally determined low detection limit is 1 attomole. In addition to the low detection limit, the SWCNTs/Au/ssDNA sensor also showed great stability, where after being kept in a refrigerator for a month at a temperature 4-8 °C its charge transfer resistance decreased by less than 1%. The sensor could be conveniently regenerated via dehybridization in hot water. Both aligned and random SWCNTs arrays have been investigated in this study and there was nearly no difference in the low limit in the detection of hepatitis B and papilloma viruses. This study illustrates that combining Au nanoparticles with the in situ fabricated SWCNTs array is a promising platform for ultrasensitive biosensing.