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.
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•A novel modification on porous boron-doped diamond electrode for determination of dopamine was developed.•The elimination of the interference was realized and a low detection limit of 54 nM for DA was obtained.•Reproducibility of the CB-Nafion/p-BDD electrode in real sample and excess interferents was validated.•Excellent stability and long-term functionality of the CB-Nafion/p-BDD electrode were confirmed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Organic phase change materials (PCM) have been regarded as one of the most promising candidates for the application of energy storage and temperature control due to their advantages in latent heat. ...However, their intrinsically low thermal conductivity (λ) is the Achilles heel, and the most common solution is to utilize thermal conductive reinforcements to fabricate composite PCMs. The research focus remains how to promote the efficiency of thermal conductive reinforcements. Here, a CNT-Cu foam hybrid reinforcement was fabricated through a high temperature tube furnace process. Different from conventional carbon film coated metal foam, CNTs with the length comparable to the pore size were radially grown on the surface of Cu foam with Ni catalysts, which can not only reduce the low-λ regions inside the foam skeleton, but also connect every branches of the foam to improve the integrity of the whole reinforcement, and the thermal conductivity of the composite was promoted to 3.49 W·m−1·K−1 from 0.105 W·m−1·K−1 of paraffin. Moreover, this reinforcement exhibited abilities to compensate the loss of latent heat and suppress the supercooling of the composite, indicating their great prospects in the application of phase change energy storage and temperature control.
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•Carbon nanotube-Cu foam hybrid reinforcements were designed and fabricated.•Carbon nanotubes grown on skeleton can improve thermal conduction of inner pores.•Thermal conductivity of the composite was 3227% higher than that of the matrix.•The reinforcement can compensate the loss of latent heat in composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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 (0.022–18.3mM), high sensitivity (1007.688 μAmM−1cm−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).
•The Ni/Cu/BDD electrode exhibits excellent long-term stability because nickel particles are embedded into the diamond forming a porous structure, which avoids the peel-off of Ni/Cu NPs during the detection.•The Ni/Cu/BDD exhibits enhanced catalytic activity compared with Ni/BDD owing to the addition of Cu nanoparticles.•The synergistic effect of nickel nanoparticles, copper nanoparticles and BDD films is well discussed for the first time.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A porous boron-doped diamond (pBDD) was made for immobilizing gold nanoparticles on BDD facets by a special process, wherein methods of magnetron sputtering and thermal catalytic treatment were ...utilized. Au nanoparticles are seated in the pores of pBDD facets and could be more stable during electrochemical tests. This hybrid structure significantly improved the electrochemical properties due to the introduction of Au nanoparticles and pores, which could increase the specific surface area. The cyclic voltammetry oxidation peak current of the Au/pBDD electrode decreased with an average daily loss of 0.02 μA and maintained approximately 90.1% of its initial value after detecting dopamine once per two days for 30 days, showing an excellent long-term electrochemical stability. In addition, the Au/pBDD electrode exhibited excellent sensitivity for the detection of DA, and the limit of detection was 0.06 μM in a linear concentration range of 0.1 μM–1 mM. This work indicates that the Au/pBDD is an appropriate material for detecting DA in a long-term tests.
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•The porous boron doped diamond (pBDD) fabricated by thermal catalytic etching with Ni as catalyst.•The Au nanoparticles-anchored porous boron doped diamond electrode is fabricated.•Au nanoparticles formed and anchored inside the pores on the pBDD facets.•The hybrid electrode shows long-term stability (30 days) and high sensitivity for dopamine detection.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Phase change materials with considerable heat effect during phase change have been regarded as one of the most promising candidates for latent thermal energy storage and thermal management. Although ...intensive efforts have been dedicated to the high-efficiency application, challenges remain in enhancing the thermal response due to their intrinsically low thermal conductivity. Here, continuous diamond-carbon nanotube foams are designed and fabricated as thermal conductive reinforcement. The unique diamond foam with extremely high thermal conductivity act as the “main channel” for thermal flow transportation, and the directly-grown, well-distributed carbon nanotube networks plays role of the “second heat channel”. Benefiting from this stable hierarchical structure, thermal conductivity of the phase change composite has been enhanced to 9.72 W m−1 K−1 from 0.105 W m−1 K−1 of paraffin matrix, representing one of the highest enhancement ever-reported. Besides this conceptual advance, we discover that the hybrid structure considerably suppresses subcooling, a common problem that causes a much lower crystallization temperature than the melting temperature of many phase change materials. The special design promises to be one of the most efficient solutions for thermal response promotion of phase change materials and their extensive application.
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•A continuous hierarchical thermal conductive reinforcement based on diamond and directly-grown carbon nanotubes was proposed and developed.•Thermal conductivity and heat charging rate of the composites were markedly promoted.•Good phase change reversibility and thermal stability were achieved.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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/cm
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.
A hybrid non-enzymatic glucose sensor made by incorporating boron doped diamond (BDD) film electrode with nickel (Ni)- encapsulated carbon nanotubes (CNTs) were facilely fabricated. The CNTs were ...grown directly on BDD films in the presence of pre-sputtered Ni layer as a catalyst by hot-filament chemical vapor deposition. The morphology and composition of the hybrid structure were assessed by scanning electron microscopy and Raman spectroscopy. As Ni layer thickness increased, the CNTs were less covered on the surface and the length of CNTs increased. The Ni particles were encapsulated into a large number of CNTs. Electrochemical results indicated that this hybrid structure significantly improved the electrochemical performance of BDD due to the increased specific surface area and synergistic effect of Ni and CNTs. The optimized glucose sensor revealed two broad linear range of 1.25 μM - 0.49 mM and 0.49 mM- 6.79 mM, with a high sensitivity of 1642.20 μA mM−1 cm−2 (R2 = 0.9988) and 1374.4 μA mM−1 cm−2 (R2 = 0.9969) respectively. In addition, the hybrid electrode exhibited a low limit of detection which was 1.0 μM (S/N = 3), and good selectivity and stability.
A novel design of Al matrix composite reinforced with diamond coated spiral tungsten wire is proposed for thermal management. Fabrication techniques of the diamond film reinforced Al matrix ...composites consist of hot filament assisted chemical vapour deposition (HFCVD) for diamond film, low-cost cold pressing and vacuum sintering of Al matrix composites. The microstructure characteristics and thermal properties of the composites have been studied. Results show that the diamond film retains its high quality and integrity after the vacuum sintering process. Even such a low content of diamond films in the filler- at most 6.5vol.% - provides a thermal conductivity of 294W/mK, about 69% higher than that of sintered Al and 79% higher than that of 6.5vol.% diamond particles reinforced Al matrix composite fabricated by the same powder metallurgy process. Finite element analysis of heat transfer within such a structure is conducted, revealing that the continuous and thick diamond framework provides continuous channels and effective thermal conductive pathways for heat transfer. This work displays a great potential of CVD diamond films reinforced metal matrix composites for thermal conduction applications.
A novel CVD diamond spiral wire/aluminium composite was designed and fabricated. A continuous diamond channel for heat transfer was designed and fabricated. Good adhesion between uncoated diamond film and pure Al was produced. The TC of the composite was enhanced by 79% compared with diamond particles/Al composites. Display omitted
•A novel CVD diamond coated W spiral wires/aluminium composite was designed and fabricated.•A continuous diamond channel for heat transfer was designed and fabricated.•Good adhesion between uncoated diamond film and pure Al was produced.•The TC of the composite was enhanced by 79% compared with diamond particles/Al composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Sputtered nickel (Ni) layers modified boron-doped diamond (BDD) electrodes for non-enzymatic glucose sensor were fabricated by the thermal catalytic etching process in the hydrogen ambient. The ...effect of Ni thickness on the thermal catalytic etching and the electrochemical behavior of Ni/BDD electrodes for glucose oxidation were investigated. Scanning electron microscopy(SEM)and Raman spectroscopy were utilized to characterize the electrode morphology and composition, respectively. Marked by different thickness and morphology of Ni layer, three kinds of surfaces were obtained after thermal catalytic etching. The first is a roughened surface with most Ni nano-particles sinking into the BDD film, the second is with Ni micro-particles presented on the BDD film, the third is with residual lamellar Ni. Electrochemical results indicated that the electrochemical behaviors of those Ni/BDD electrodes were related to the surface structure. The second Ni/BDD electrode has the limit of detection (LOD) of 1.23μM with a sensitivity of 839.3μAmM−1cm−2, which was ascribed to the numerous agglomerated Ni nano- and micro-particles presented on the roughed surface.
•The Ni modified BDD electrodes are prepared by thermal catalytic etching.•Three Ni films with Different thickness are sputtered on BDD.•Three feature roughened surface structures are obtained.•The Ni/BDD-1min electrode exhibited the best electrochemical performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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.
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•An alternative growth method for yielding carbon nanomaterials was proposed.•The process-dependent formation mechanism was studied.•Enhanced field emission performance was realized by adding external fields.•Essence of field emission was proved to be a combination of several mechanisms.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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