Chemical vapor deposited diamonds on Re substrate for the application of field emission

Boron-doped diamond (BDD) films were deposited on rhenium substrates using methane/hydrogen as reactant gases by hot filament chemical vapor deposition (HFCVD). The morphology, band structures and crystalline structure of the BDD films were characterized by the scanning electron microscope (SEM), Raman spectroscopy and X-ray diffractometer (XRD), respectively. The effects of the pre-treated on nucleation and quality of the diamond film were investigated. The mixture of sulfur acid and nitric acid enhanced diamond nucleation much more greatly than that of single acid. The highly boron-doped diamond films were deposited on rhenium substrate. The field emission characteristics of these films were analyzed. The minimum resistivity of doped diamond films reached 10? 2 ? cm. Field emission studies revealed that the BDD film grown on rhenium substrate had the low threshold field (3.3 v/?m).</p

Chemical vapor deposited diamonds on Re substrate for the application of field emission

Boron-doped diamond (BDD) films were deposited on rhenium substrates using methane/hydrogen as reactant gases by hot filament chemical vapor deposition (HFCVD). The morphology, band structures and crystalline structure of the BDD films were characterized by the scanning electron microscope (SEM), Raman spectroscopy and X-ray diffractometer (XRD), respectively. The effects of the pre-treated on nucleation and quality of the diamond film were investigated. The mixture of sulfur acid and nitric acid enhanced diamond nucleation much more greatly than that of single acid. The highly boron-doped diamond films were deposited on rhenium substrate. The field emission characteristics of these films were analyzed. The minimum resistivity of doped diamond films reached 10? 2 ? cm. Field emission studies revealed that the BDD film grown on rhenium substrate had the low threshold field (3.3 v/?m).</p

Nickel-Encapsulated Carbon Nanotubes Modified Boron Doped Diamond Hybrid Electrode for Non-Enzymatic Glucose Sensing

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 ?M - 0.49 mM and 0.49 mM- 6.79 mM, with a high sensitivity of 1642.20 ?A mM?1 cm?2 (R2 = 0.9988) and 1374.4 ?A mM?1 cm?2 (R2 = 0.9969) respectively. In addition, the hybrid electrode exhibited a low limit of detection which was 1.0 ?M (S/N = 3), and good selectivity and stability.</p

Nickel-Encapsulated Carbon Nanotubes Modified Boron Doped Diamond Hybrid Electrode for Non-Enzymatic Glucose Sensing

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 ?M - 0.49 mM and 0.49 mM- 6.79 mM, with a high sensitivity of 1642.20 ?A mM?1 cm?2 (R2 = 0.9988) and 1374.4 ?A mM?1 cm?2 (R2 = 0.9969) respectively. In addition, the hybrid electrode exhibited a low limit of detection which was 1.0 ?M (S/N = 3), and good selectivity and stability.</p

Hydrophilic modification of carbon nanotube to prepare a novel porous copper network-carbon nanotube/erythritol composite phase change material

Carbon nanotube(CNT)-based materials is a promising thermally conductive filler for phase change materials(PCM), while its widely applications are greatly hampered by the hydrophobicity of CNTs. In this work, a novel composite PCM based on hydrophilic modified porous copper network(PCN)-CNT filler and erythritol(Ery) was explored. The hydrophilic modified PCN-CNT filler can be obtained upon heat treatment. During the heat treatment process, defects and oxygen-containing functional groups formed on the surface of CNTs, thus improving the hydrophilicity of CNTs. The optimum heat treatment temperature is determined to be 500°C, at which the adsorptive capacity of the modified filler reaches 88.2% for Ery, larger than 28.2% of the unmodified one. The as-prepared PCN-CNT/Ery composite PCM maintains a similar melting point to that of pure Ery, and its latent heat is as high as 213.2 J g−1. The thermal conductivity of PCN-CNT/Ery composite PCMs increases by 892% and 51% compared with pure Ery and PCN/Ery composite PCM, respectively. Moreover, the PCN-CNT filler could help improve the supercooling of Ery significantly. Besides, the enthalpy loss of the composite PCM was negligible after 20 cycles. Defects and functional groups are introduced on the surface of CNTs by heat treatment. Therefore, the heat-treated CNTs showed a transition from hydrophobic to hydrophilic, thus improving the interface compatibility of PCN-CNT and Ery phases in composites. Highly conductive PCN-CNT filler modified under the optimal heat treatment temperature compound with pure Ery by vacuum impregnation, significantly improving the thermal transfer properties of Ery. </p

High-sensitivity, selective determination of dopamine using bimetallic nanoparticles modified boron-doped diamond electrode with anodic polarization treatment

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 ?M in a linear concentration range of 0.05–100 ?M with the sensitivity up to 1.99 ?A ?M?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.</p

High-sensitivity, selective determination of dopamine using bimetallic nanoparticles modified boron-doped diamond electrode with anodic polarization treatment

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 ?M in a linear concentration range of 0.05–100 ?M with the sensitivity up to 1.99 ?A ?M?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.</p

Non-Enzymatic Glucose Sensor Based on Hierarchical Au/Ni/Boron-Doped Diamond Heterostructure Electrode for Improving Performances

A novel hierarchical Au/Ni/boron-doped diamond (BDD) heterostructure electrode was fabricated by two-step heat-treatment. The heterostructure that hierarchical Au/Ni nanoparticles are embedded on the surface of BDD was demonstrated by transmission electron microscope (TEM). Cyclic voltammetry (CV) and amperometric detection were used to test electrochemical properties of the prepared electrodes. The Au/Ni/BDD electrode exhibited enhanced catalytic activity and stability in glucose detection, as compared to that of the Au/BDD and Ni/BDD electrodes. On the optimal NaOH concentration and applied potential, the Au/Ni/BDD electrode exhibited an extremely wide detection range of 0.005–32 mM with high sensitivity of 1229.5 ?AmM?1cm?2 and an excellent long-term stability (maintains 94.8% of initial current after one month). In addition, the prepared electrode also exhibited a low detection limit of 2 ?M (S/N = 3), good selectivity and reproducibility. At last, the reasons for enhanced catalytic activity and excellent stability of Au/Ni/BDD electrode were discussed.</p

Antifouling nanoporous diamond membrane for enhanced detection of dopamine in human serum

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 ?mol 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.</p

Antifouling nanoporous diamond membrane for enhanced detection of dopamine in human serum

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 ?mol 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.</p