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High salinity wastewater is characterized by high salt content, a large number of organic pollutants and difficulty in biochemical degradation, which has become a major problem in industrial wastewater treatment. In this article, the electrochemical oxidation technology was used to treat high salinity wastewater. The effects of temperature, current density, pH and additives on the removal effect of high salinity wastewater were investigated to optimize the process parameters. The results show that the best degradation effect is when the current density is 21.43 mA cm−2, pH = 2, the temperature is 60 °C, and electric field activates additional persulfate. After purification of high salt wastewater, the evaporated salt can be utilized as a resource. The industrial cost of degradation was estimated, and its economic benefits were calculated. This work will provide a theoretical and experimental basis for treating high salt wastewater by boron-doped diamond (BDD) electrochemical degradation technology. HIGHLIGHTS BDD + PS System can efficiently degrade organic matter with low energy consumption but high cost.; After purification of high salt wastewater, the evaporated salt can be utilized as resources.; The industrial cost of degradation was estimated and its economic benefits were calculated.

In this work, we proposed a novel modification technique to immobilize nanoparticles by the nanopores on a boron-doped diamond surface, preventing the aggregation of nanoparticles physically and improving the stability of nanoparticles layer by the anchoring effect. All the exposed surfaces of a bare boron-doped diamond were etched into nanoporous form and larger electrochemically active surface area was obtained on the porous boron-doped diamond electrode. The carbon black nanoparticles modified porous boron-doped diamond electrode showed good selectivity to separate the oxidation potential of three molecules, but led to an extra increase in the peak current of dopamine (DA). The carbon black/Nafion modified porous diamond electrode effectively suppress the oxidation current of ascorbic acid (AA), enhancing the sensitivity of DA. The dual layer treatment enables a wide linear range, 0.1–100 μM and a low limit of detection, 54 nM for DA detection, which is almost unaffected by the excess AA and uric acid (UA). At last, real sample tests of the carbon black/Nafion modified porous diamond electrode was validated by applying to the detection of DA in human serum and dopamine hydrochloride injection, which were found to be promising at our preliminary experiments. Additionally, the fabricated carbon black/Nafion modified porous diamond electrode also demonstrated good stability and long-term functionality.

Graphene nanosheets are widely used in anti-corrosion polymeric coating as filler, owing to the excellent electrochemical inertness and barrier property. However, as the arrangement of graphene nanosheets is difficult to form a perfect layered structure, polymeric coating with graphene nanosheets usually needs micron-scale thickness to ensure the enhancement of corrosion protection. In this work, layer-by-layer stacked graphene nanocoatings were fabricated on stainless steel by self-assembly based on Marangoni effect. The anti-corrosion property of graphene coatings were studied through Tafel polarization curves, electrochemical impedance spectroscopy and accelerated corrosion test with extra applied voltage. The self corrosion current density of optimized three-layered graphene coated sample was one quarter of that of bare stainless steel. And the self corrosion potential of optimized sample is increased to -0.045 V. According to the results, graphene nanocoatings composed of layered nanosheets exhibits good anti-corrosion property. Besides, the self-assembly method provide a promising approach to make layered-structure coating for other researches about 2D material nanosheets.

Selective detection of dopamine is still a challenge due to the strong interference from ascorbic acid (AA). A hybrid dopamine electrochemical sensor was fabricated by boron-doped diamond (BDD) film co-modified with gold nanoparticles and graphite-coated nickel nanoparticles (Au-C@Ni/BDD). Highly sensitive and selective detection toward dopamine was achieved by multiple electrochemical anodic polarization treatment (EAPT) with relatively mild voltage (+ 1.6 V vs. Ag/AgCl) on Au-C@Ni/BDD electrode. Specifically, the oxidation peak separation between ascorbic acid and dopamine reached 166 mV, and the limit of detection of dopamine was as low as 0.015 μM in a linear concentration range of 0.05–100 μM with the sensitivity up to 1.99 μA μM−1 cm−2 even in the presence of interference of high-level AA. These could be ascribed to the electrocatalytically active sites and functional oxygen-containing groups of the hybrid electrodes produced by the EAPT and the excellent catalytical activity of gold nanoparticles.

The bipolar plate is the major component of proton-exchange membrane fuel cells and also a critical contributor to the fuel cell performance. Metallic bipolar plate (MBP) has high impact resistance but its poor chemical stability limits the service lifetime and stack stability. One of the feasible methods to enhance the corrosion resistance of MBPs is the formation of conductive protective coatings on the MBP surface. In this work, nanostructured carbon coatings were deposited on stainless steel by chemical vapor deposition using the substrate itself as catalysts. Under the optimized conditions, the corrosion potential of carbon coatings with dense spherical structure on stainless steel (2.1 VRHE) is much higher than that of uncoated one (1.2 VRHE), and even greater than that of commercial graphite bipolar plates (1.7 VRHE), showing 75% and 23.5% improvement in corrosion resistance, respectively. Moreover, the corrosion current density of stainless steel with dense sphere-assembled coatings decreases to 0.2 mA/cm2, which is two orders of magnitude lower than that of graphite bipolar plates (27.4 mA/cm2) at the same applied potential (2.2 VRHE). The coated stainless steel with excellent anticorrosion properties has potential applications for MBPs in proton-exchange membrane fuel cells, electrochemical treatment of waste water, and current collectors in lithium-ion batteries.

In vivo tracking or in vitro real sample analysis by electrochemistry is one of the most straight and useful methods in biosensor field. However, surface biofouling of electrodes by non-specific protein adsorption is inevitable and usually leads to a decrease in sensitivity. Here, we developed a Nafion-coated porous boron-doped diamond (NAF/pBDD) electrode with hydrophobic nanostructures to minimize the biofouling effect and selectively detect dopamine (DA). Larger active area was obtained by this procedure compared to a bare diamond electrode. The as-prepared electrode shows excellent antifouling property and enrichment capacity toward selective detection of dopamine (DA). The low background current of the BDD electrode and the enhanced signals enables a lower detection limit, 42 nmol L−1, and a wider linear range, 0.1–110 μmol L−1, for determination of DA in human serum. Additionally, the facile modified electrode demonstrated renewable property and long-term stability due to the fact that the antifouling nanostructures belong to its own.

Due to the special shape of cutting or grinding tools used nowadays, hot filament (HF)-substrate distance is usually unavoidable during the process of diamond deposition by hot filament chemical vapor deposition (HFCVD), which will lead to difficult deposition process for nanocrystalline diamond (NCD). Based on this problem, the coupling effects of different CH4/H2/Ar gas ratios and HF-substrate distances on the growth of NCD films are systematically studied. SEM and Raman are used to analyze the surface morphology and sp3/sp2 contents of the diamond films deposited on different areas of each specimen. The results indicate that the proper increase of HF-substrate distance and concentration of CH4 or Ar encourage the growth of NCD. Under the condition of lower concentration of CH4 or Ar, NCD with uniform grain size can also be realized at a certain range of HF-substrate distance. A graph that shows the growth conditions of MCD, MCD/NCD and NCD is creatively presented by summarizing the deposition parameters and experimental results. This work provides a path to coat NCD onto the special-shaped cutting or grinding tools by HFCVD.

In this paper, boron-doped diamond (BDD) electro-activated persulfate was studied to decompose malachite green (MG). The degradation results indicate that the decolorization performance of MG for the BDD electro-activated persulfate (BDD-EAP) system is 3.37 times that of BDD electrochemical oxidation (BDD-EO) system, and BDD-EAP system also exhibited an enhanced total organic content (TOC) removal (2.2 times) compared with BDD-EO system. Besides, the degradation parameters such as persulfate concentration, current density, and pH were studied in detail. In a wider range of pH (2–10), the MG can be efficiently removed (>95%) in 0.02 M persulfate solution with a low current density of 1.7 mA/cm2 after 30 min. The BDD-EAP technology decomposes organic compounds without the diffusion limitation and avoids pH adjustment, which makes the EO treatment of organic wastewater more efficient and more economical.

The surficial micro/nanotopography and physiochemical properties of titanium implants are essential for osteogenesis. However, these surface characters’ influence on stem cell behaviors and osteogenesis is still not fully understood. In this study, titanium implants with different surface roughness, nanostructure, and wettability were fabricated by further nanoscale modification of sandblasted and acid-etched titanium (SLA: sandblasted and acid-etched) by H2O2 treatment (hSLAs: H2O2 treated SLA). The rat bone mesenchymal stem cells (rBMSCs: rat bone mesenchymal stem cells) are cultured on SLA and hSLA surfaces, and the cell behaviors of attachment, spreading, proliferation, and osteogenic differentiation are further analyzed. Measurements of surface characteristics show hSLA surface is equipped with nanoscale pores on microcavities and appeared to be hydrophilic. In vitro cell studies demonstrated that the hSLA titanium significantly enhances cell response to attachment, spreading, and proliferation. The hSLAs with proper degree of H2O2 etching (h1SLA: treating SLA with H2O2 for 1 hour) harvest the best improvement of differentiation of rBMSCs. Finally, the osteogenesis in beagle dogs was tested, and the h1SLA implants perform much better bone formation than SLA implants. These results indicate that the nanoscale modification of SLA titanium surface endowing nanostructures, roughness, and wettability could significantly improve the behaviors of bone mesenchymal stem cells and osteogenesis on the scaffold surface. These nanoscale modified SLA titanium scaffolds, fabricated in our study with enhanced cell affinity and osteogenesis, had great potential for implant dentistry.

Considering the vital physiological functions of dopamine (DA) and uric acid (UA) and their coexistence in the biological matrix, the development of biosensing techniques for their simultaneous and sensitive detection is highly desirable for diagnostic and analytical applications. Therefore, Ti3C2Tx/rGO heterostructure with a double-deck layer was fabricated through electrochemical reduction. The rGO was modified on a porous Ti3C2Tx electrode as the biosensor for the detection of DA and UA simultaneously. Debye length was regulated by the alteration of rGO mass on the surface of the Ti3C2Tx electrode. Debye length decreased with respect to the rGO electrode modified with further rGO mass, indicating that fewer DA molecules were capable of surpassing the equilibrium double layer and reaching the surface of rGO to achieve the voltammetric response of DA. Thus, the proposed Ti3C2Tx/rGO sensor presented an excellent performance in detecting DA and UA with a wide linear range of 0.1–100 μM and 1–1000 μM and a low detection limit of 9.5 nM and 0.3 μM, respectively. Additionally, the proposed Ti3C2Tx/rGO electrode displayed good repeatability, selectivity, and proved to be available for real sample analysis.

This communication reports nickel hydroxide nanoplates grown on nickel foam (NF) by one-step water bath treatment of NF in nitric acid solution. The reaction temperature and duration were critical to the formation of nanoplates. Moreover, the Ni(OH)2 electrode on nickel foam (Ni(OH)2/NF) exhibited high performance and prominent stability toward the hydrogen evolution reaction (HER) in an alkaline solution. The mentioned finding will be expected to broaden the development of Ni(OH)2-based binder-free electrodes for electrochemical applications.

The development of low-cost electrocatalysts with high performance toward the hydrogen evolution reaction (HER) is crucial for large-scale and clean hydrogen production. Herein, we report a facile synthesis of Co/CoO hybrids with oxygen vacancies on carbon cloth (CC) via the calcination treatment of a Co3O4 precursor in a reducing atmosphere (H2/Ar). Moreover, to avoid delamination and cracks during heat treatment and catalyst abscission during the HER test, the precursor of Co(OH)2 was stabilized on CC by the anion intercalation method, resulting in robust adhesion between the film and substrate. The as-prepared Co/CoO hybrids rooted on the CC substrate possessed good charge transfer properties, favorable kinetics, abundant active sites, and robust adhesion. A suitable reducing atmosphere was crucial for high catalytic activity. By optimizing, the sample obtained in a 30% H2/Ar atmosphere (Co/CoO-30) possessed an optimal balance between Co/CoO and oxygen vacancies, exhibiting optimum HER performance with the smallest overpotential of 158 mV at 10 mA cm−2 and Tafel slope of 68.1 mV dec−1 as well as good stability, operating for at least 24 h.

Low dimensional Bi2S3 materials are excellent for use in photodetectors with excellent stability and fast response time. In this work, we developed a visible light sensor with good performance based on surface acoustic wave (SAW) devices using Bi2S3 nanobelts as the sensing materials. The SAW delay-line sensor was fabricated on ST-cut quartz with a designed wavelength of 15.8 microns using conventional photolithography techniques. The measured center frequency was 200.02 MHz. The Bi2S3 nanobelts prepared by a facile hydrothermal process were deposited onto SAW sensors by spin-coating. Under irradiation of 625 nm visible light with a power intensity of 170 μW cm−2, the sensor showed a fast and large response with a frequency upshift of 7 kHz within 1 s. The upshift of the frequency of the SAW device is mainly attributed to the mass loading effect caused by the desorption of oxygen from the Bi2S3 nanobelts under visible light radiation.

ZnO is a promising gas sensing material for its excellent gas sensing response characteristics and long-term stability. Moreover, the improvement in the sensitivity and response speed of ZnO gas sensors can be achieved by the nanostructure fabrication. This paper proposes a facile method to deposit ZnO nanospirals using glancing angle deposition (GLAD) for application in nitric oxide (NO) sensors. ZnO nanospirals with porous characteristics have larger relative surface area and more active surfaces, compared with dense ZnO thin film. A sensor using nanospiral ZnO film shows a response factor of 16.9 to 100 ppb NO at 150 °C in 40% RH, which is 3 times larger than that of the sensor using dense ZnO film. Such a ZnO nanospiral sensor system can detect NO as low as 10 ppb which is below the NO concentration (>30 ppb) in exhaled breath of patients with asthma. The effects of working temperature and humidity on the sensor performance were investigated systematically in this work. Moreover, the sensor response showed a good selectivity to NO and high stability as the time increased up to 24 days. NO gas sensing mechanism was discussed in detail and nanospiral ZnO film sensors are promisingly applicable for exhaled human breath application compared with some other NO sensors.

Along with the technology evolution for dense integration of high-power, high-frequency devices in electronics, the accompanying interfacial heat transfer problem leads to urgent demands for advanced thermal interface materials (TIMs) with both high through-plane thermal conductivity and good compressibility. Most metals have satisfactory thermal conductivity but relatively high compressive modulus, and soft silicones are typically thermal insulators (0.3 W m-1 K-1). Currently, it is a great challenge to develop a soft material with the thermal conductivity up to metal level for TIM application. This study solves this problem by constructing a graphene-based microstructure composed of mainly vertical graphene and a thin cap of horizontal graphene layers on both the top and bottom sides through a mechanical machining process to manipulate the stacked architecture of conventional graphene paper. The resultant graphene monolith has an ultrahigh through-plane thermal conductivity of 143 W m-1 K-1, exceeding that of many metals, and a low compressive modulus of 0.87 MPa, comparable to that of silicones. In the actual TIM performance measurement, the system cooling efficiency with our graphene monolith as TIM is 3 times as high as that of the state-of-the-art commercial TIM, demonstrating the superior ability to solve the interfacial heat transfer issues in electronic systems.

Boron-doped diamond (BDD) has proved to be an ideal anode material for the electrolysis of organic sewage. However, the existing two dimensional BDD electrodes with small active area and low mass transfer rates, limit their further improvement in degradation efficiency. In this paper, a novel three dimensional macroporous BDD (3D-BDD) foam electrode with a structure of evenly distributed pores and interconnected networks in which wastewater can flow freely was prepared using a simple and reproducible method. Compared to two dimensional BDD electrodes of the same geometry, the electro-active surface area of 3D-BDD electrode increased by ˜20 times, and the electrochemical oxidation reaction rate constant of RB-19 increased by ˜350 times. Under optimized conditions, the energy consumption reduced to a minimum of 0.03 kWh(gTOC) −1, and the MCE reach a maximum of 325.86%.

A series of carbon-coated nickel nanoparticle modified boron-doped diamond (Ni(C)-BDD) composite electrodes with different amounts of carbon coating were fabricated. The effects of heat treatment time on the electrochemical performance of the Ni(C)-BDD electrodes for glucose detection were investigated. The morphology and composition of the composite electrodes were assessed by scanning electron microscopy and Raman spectroscopy. Ni catalyzed the carbon inside boron-doped diamond (BDD) into graphite layer which was coated on the surface of Ni nanoparticles at high temperature. As thermal catalytic treatment time prolonged, the carbon coated on Ni nanoparticles became more and more obvious. Electrochemical results indicate that the Ni(C)-BDD composite electrode shows excellent electrochemical performance for glucose oxidation. Compared to the 5 min-Ni(C)-BDD electrode, the 30 and 60 min-Ni(C)-BDD electrodes need longer heat treatment time, and in return the Ni nanoparticles are covered by more carbon layer, and the current response after one-month measurement is 81.11% and 81.55%, respectively. The 60 min-Ni(C)-BDD electrode has a sensitivity of 1130 and 420 μA·mM−1·cm−2 in the detection range of 1 μM to 4 mM and 4 to 10 mM, respectively, its LOD is 0.69 μM, and the current response after one month's test remains 81.55% of the initial value. The composite electrode has high sensitivity, good selectivity and long-term stability for glucose detection.

A Ni/Cu/boron-doped diamond (Ni/Cu/BDD) complex electrode for non-enzymatic glucose electrochemical detection was prepared by a simple two-step heat treatment method. Scanning electron microscopy (SEM), Raman spectroscopy and electrochemical workstation were used to characterize the surface morphology, composition and electrochemical properties of the electrode, respectively. The results showed that Ni reacted with BDD under high temperature catalytic conditions forming a porous structure, and stabilized Cu on the surface of BDD due to the superior wettability between Cu and Ni. Compared to Ni/BDD and Cu/BDD electrodes, Ni/Cu/BDD electrode exhibited enhanced catalytic activity in glucose detection, such as an extremely wide detection range (0.022–18.3 mM), high sensitivity (1007.688 μAmM−1 cm−2, which was 1.28 times higher than that of the Ni/BDD electrode), great selectivity and excellent long-term stability (93.3% after one month).

Surface acoustic wave (SAW) sensors have great advantages in real-time and in-situ gas detection due to their wireless and passive characteristics. Using nanostructured sensing materials to enhance the SAW sensor’s responses has become a research focus in recent years. In this paper, solution-processed PbS colloidal quantum dots (CQDs) were integrated into quartz SAW devices for enhancing the performance of NO2 detection operated at room temperature. The PbS CQDs were directly spin-coated onto ST-cut quartz SAW delay lines, followed by a ligand exchange treatment using Pb(NO3)2. Upon exposure to 10 ppm of NO2 gas, the sensor coated with untreated PbS CQDs showed response and recovery times of 487 s and 302 s, and a negative frequency shift of −2.2 kHz, mainly due to the mass loading effect caused by the absorption of NO2 gas on the surface of the dense CQD film. Whereas the Pb(NO3)2-treated sensor showed fast response and recovery times of 45 s and 58 s, and a large positive frequency shift of 9.8 kHz, which might be attributed to the trapping of NO2 molecules in the porous structure and thus making the film stiffer. Moreover, the Pb(NO3)2-treated sensor showed good stability and selectivity at room temperature.

Potassium (K+) ions are essential minerals that are important in maintaining fluid and electrolyte balance in biological systems and regulating bodily functions. However, abnormal K+ concentration level will cause numerous health problems or diseases. Therefore, the effective detection of physiological K+ level is very important in the healthcare field. In this work, we designed, fabricated and characterized solution-gated field effect transistors (FETs) based on high quality CVD graphene for highly sensitive and selective detection of K+ ions. O2 plasma pre-processing for 10 s yielded a limit of detection (LOD) down to 0.058 pM, and a linear dynamic range spanning from sub-0.1 pM to 100 nM. Meanwhile, as the G-quadruplex conformation possesses strong affinity for K+, the FETs exhibit excellent discrimination against other common cations, such as Na+ and Fe3+. As a result, the solution-gated graphene FETs with enhanced sensitivity and selectivity for K+ can be applied to health monitoring and disease prevention.

Colloidal quantum dots (CQDs) have shown their advantages in gas-sensing applications due to their extremely small particle size and facile solution based processes. In this study, a high sensitivity of surface acoustic wave (SAW) NO2 sensor was demonstrated using SnS CQDs as the sensing layer. The delay line based SAW device with a resonant frequency of 200 MHz were fabricated on ST-cut quartz substrate. The SnS CQDs with average sizes of 5.0 nm were synthesized and deposited onto SAW sensors using a spin-coating method. The fabricated SAW sensor was capable of detecting a low concentration of NO2 gas at room temperature with a good efficiency and selectivity e.g., with a 1.8 kHz decrease of center frequency of the SAW delay line when exposed to 10 ppm NO2 at room temperature.

To enhance the field emission performance and understand the emission essence of carbon materials, carbon films with different morphology and phase composition were fabricated by regulating the reactive gas flow ratio in a hot filament chemical vapor deposition system with the assistance of electric field and magnetic field. The characterization of carbon film quality and measurement of their field emission performance indicated that carbon nanostructures, including nanoclusters, nanopillars and nanotips, which were determined by the methane concentration in the process, were formed under the assistance of electric field. Further magnetic field assistance could lead to the formation of finer nanostructures with higher crystallinity. Field emission performance was highly dependent on the morphology and phase composition of the carbon films. Among all the samples, carbon nanotips, deposited in high methane concentration with the co-assistance of magnetic and electric field, possessed the best field emission performance, with the lowest turn-on field of 6.5 V·μm−1 (J = 10 μA·cm−2). Besides, a comparative study on the fitting degree of several conduction mechanisms revealed that the essence of field emission was the combination of several emission mechanisms, which was also dependent on the morphology and phase composition of these carbon films.

Given the thermal management problem aroused by increasing power densities of electronic components in the system, graphene-based papers have raised considerable interest for applications as thermal interface materials (TIMs) to solve interfacial heat transfer issues. Significant research efforts have focused on enhancing the through-plane thermal conductivity of graphene paper, however, for practical thermal management applications, reducing the thermal contact resistance between graphene paper and the mating surface is also a challenge to be addressed. Here, a strategy aimed at reducing the thermal contact resistance between graphene paper and the mating surface to realize enhanced heat dissipation was demonstrated. For this, graphene paper was decorated with polydopamine EGaIn nanocapsules using a facile dip-coating process. In practical TIM application, there was a decrease in the thermal contact resistance between the TIMs and mating surface after decoration (from 46 to 15 K mm2 W−1), which enabled the decorated paper to realize a 26% enhancement of cooling efficiency compared with the case without decoration. This demonstrated that this method is a promising route to enhance the heat dissipation capacity of graphene-based TIMs for practical electronic cooling applications.

The rapid development of integrated circuits and electronic devices creates a strong demand for highly thermally conductive yet electrically insulating composites to efficiently solve "hot spot" problems during device operation. On the basis of these considerations, hexagonal boron nitride nanosheets (BNNS) have been regarded as promising fillers to fabricate polymer matrix composites. However, so far an efficient approach to prepare ultrahigh-aspect-ratio BNNS with large lateral size while maintaining an atomically thin nature is still lacking, seriously restricting further improvement of the thermal conductivity for BNNS/polymer composites. Here, a rapid and high-yield method based on a microfluidization technique is developed to obtain exfoliated BNNS with a record high aspect ratio of ≈1500 and a low degree of defects. A foldable and electrically insulating film made of such a BNNS and poly(vinyl alcohol) (PVA) matrix through filtration exhibits an in-plane thermal conductivity of 67.6 W m

Chloramphenicol (CAP) is a harmful compound associated with human hematopathy and neuritis, which was widely used as a broad-spectrum antibacterial agent in agriculture and aquaculture. Therefore, it is significant to detect CAP in aquatic environments. In this work, carbon nanotubes/silver nanowires (CNTs/AgNWs) composite electrodes were fabricated as the CAP sensor. Distinguished from in situ growing or chemical bonding noble metal nanomaterials on carbon, this CNTs/AgNWs composite was formed by simple solution blending. It was demonstrated that CNTs and AgNWs both contributed to the redox reaction of CAP in dynamics, and AgNWs was beneficial in thermodynamics as well. The proposed electrochemical sensor displayed a low detection limit of up to 0.08 μM and broad linear range of 0.1–100 μM for CAP. In addition, the CNTs/AgNWs electrodes exhibited good performance characteristics of repeatability and reproducibility, and proved suitable for CAP analysis in real water samples.