Electrochemical incineration of dimethyl phthalate by anodic oxidation with boron-doped diamond electrode

The anodic oxidation of aqueous solutions containing dimethyl phthalate （DMP） up to 125 mg/L with sodium sulfate （Na2SO4） as supporting electrolyte within the pH range 2.0-10.0 was studied using a one-compartment batch reactor employing a boron-doped diamond （BDD） as anode. Electrolyses were carded out at constant current density （1.5-4.5 mA/cm^2）. Complete mineralization was always achieved owing to the great concentration of hydroxyl radical （-OH） generated at the BDD surface. The effects of pH, apparent current density and initial DMP concentration on the degradation rate of DMP, the specific charge required for its total mineralization and mineralization current efficiency were investigated systematically. The mineralization rate of DMP was found to be pH-independent and to increase with increasing applied current density. Results indicated that this electrochemical process was subjected, at least partially, to the mass transfer of organics onto the BDD surface. Kinetic analysis of the temporal change of DMP concentration during electrolysis determined by High Performance Liquid Chromatography （HPLC） revealed that DMP decay under all tested conditions followed a pseudo first-order reaction. Aromatic intermediates and generated carboxylic acids were identified by Gas Chromatography- Mass Spectrometry （GC-MS） and a general pathway for the electrochemical incineration of DMP on BDD was proposed.

Synthesis and characterization of p-type boron-doped IIb diamond large single crystals

High-quality p-type boron-doped IIb diamond large single crystals are successfully synthesized by the temperature gradient method in a china-type cubic anvil high-pressure apparatus at about 5.5 GPa and 1600 K. The morphologies and surface textures of the synthetic diamond crystals with different boron additive quantities are characterized by using an optical microscope and a scanning electron microscope respectively. The impurities of nitrogen and boron in diamonds are detected by micro Fourier transform infrared technique. The electrical properties including resistivities, Hall coefficients, Hall mobilities and carrier densities of the synthesized samples are measured by a four-point probe and the Hall effect method. The results show that large p-type boron-doped diamond single crystals with few nitrogen impurities have been synthesized. With the increase of quantity of additive boron, some high-index crystal faces such as {113} gradually disappear, and some stripes and triangle pits occur on the crystal surface. This work is helpful for the further research and application of boron-doped semiconductor diamond.

Synthesis of Boron-doped Diamond/Porous Ti Composite Materials——Effect of Carbon Concentration

Highly boron-doped diamond films were deposited on porous titanium substrates by hot filament chemical vapor deposition technique. The morphology variation of highly boron-doped diamond films grown on porous titanium substrates was investigated, and the effects of carbon concentration on nucleation density and diamond growth were also studied. The continuous change of surface morphology and structure of diamond film were characterized by scanning electron microscopy. The structures of diamond film and interlayer were analyzed by X-ray diffraction. The quality of boron-doped diamond film was confirmed by visible Raman spectroscopy. The experimental results reveal that surface morphology and quality of boron-doped diamond films are various due to the change of carbon concentration. The thickness of intermediate layer decreases with the carbon concentration increasing.

Ohmic and Schottky contacts of hydrogenated and oxygenated boron-doped single-crystal diamond with hill-like polycrystalline grains

Hill-like polycrystalline diamond grains(HPDGs)randomly emerged on a heavy boron-doped p+single-crystal diamond(SCD)film by prolonging the growth duration of the chemical vapor deposition process.The Raman spectral results confirm that a relatively higher boron concentration(~1.1×10^(21) cm^(-3))is detected on the HPDG with respect to the SCD region(~5.4×10^(20) cm^(-3)).It demonstrates that the Au/SCD interface can be modulated from ohmic to Schottky contact by varying the surface from hydrogen to oxygen termination.The current-voltage curve between two HPDGs is nearly linear with either oxygen or hydrogen termination,which means that the HPDGs provide a leakage path to form an ohmic contact.There are obvious rectification characteristics between oxygen-terminated HPDGs and SCD based on the difference in boron doping levels in those regions.The results reveal that the highly boron-doped HPDGs grown in SCD can be adopted as ohmic electrodes for Hall measurement and electronic devices.

Electrochemical Detection of Clenbuterol in Pig Liver at Pyrrole DNA Modified Boron-doped Diamond Electrode

The direct detection of clenbuterol（CL） in pig liver without any extraction separation at a pyrrole-DNA modified boron-doped diamond（BDD） electrode is reported. The pyrrole-DNA modified BDD electrode has a strong electrocatalytic effect on the redox reaction of CL. One oxidization and two reduction peaks of CL appear at 340. 2, 299. 8 and 166. 6 mV（ versus SCE）, respectively. The pyrrole polymer alone cannot electrocatalyze the above reaction at a BDD electrode ; the electrocatalytic effect of a BDD electrode modified with DNA membrane is unsufficient for the analytical detection of CL; the replacement of boron-doped diamond by glass carbon makes the electrocatalytic reaction impossible ; the redox process is pH dependent. The influences of various experimental parameters on the pyrrole-DNA modified BDD electrode were investigated. A sensitive cyclic vohammetric response for CL was obtained in a linear range from 3.4 × 10^-6 to 5 × 10^ -4 mol/L with a detection limit of 8.5 × 10^-7 mol/L. A mean recovery of 102. 7% of CL in the pig liver sample solution and a reproducibility of 3.2% were obtained.

Electroanalytical Investigation on Paracetamol on Boron-Doped Diamond Electrode by Voltammetry

An electroanalytical method was developed for the direct quantitative determination of paracetamol in tablets based on its oxidation behavior. The electrochemical oxidation and determination of paracetamol were easily carried out on born-doped diamond (BDD) electrode using two voltammetric techniques (CV and DPV). The electrochemical measurements performed by cyclic voltammetric (CV) and differential pulse voltammetry (DPV) techniques were carried out using a cathodically pretreated boron-doped diamond electrode in HClO4 and KClO4 electrolytes. HClO4 was then selected for analytical purposes and scan rate studies were also completed. The oxidation of the paracetamol is found to be irreversible and a diffusion-controlled nature of the paracetamol oxidation peak was established. A linear calibration curve for DPV analysis was constructed in the paracetamol concentration range from 0 μM to 13.87 μM, with 0.16 μM and 0.55 μM as the detection and quantification limit respectively.

Analytical Determination of Benzophenone-3 in Sunscreen Preparations Using Boron-Doped Diamond Electrodes

A new electroanalytical procedure was developed for the determination of Benzophenone-3 (BENZO) in commercial sunscreen as the active ingredient. The procedure is based on the use of electrochemical methods as cyclic and square-wave voltammetry, with boron-doped diamond (BDD) electrodes. The reduction of BENZO in Britton-Robinson buffer (0.1 mol●L–1) using this type of electrode gives rise to one irreversible peak in –1.30 V (versus Ag/AgCl) in presence of cationic surfactant cetyltrimethylammonium bromide (CTABr). The proposed electrochemical method was successfully applied to the analysis of commercially available pharmaceutical preparations.

White electroluminescence of n-ZnO:Al/p-diamond heterostructure devices

An n-ZnO：A1/p-boron-doped diamond heterostructure electroluminescent device is produced, and a rectifying be- havior can be observed. The electroluminescence spectrum at room temperature exhibits two visible bands centred at 450 nm-485 nm （blue emission） and 570 nm-640 nm （yellow emission）. Light emission with a luminance of 15 cd/m2 is observed from the electroluminescent device at a forward applied voltage of 85 V, which is distinguished from white light by the naked eye.

Schottky photodiode using submicron thick diamond epilayer for flame sensing

The sensing of a flame can be performed by using wide-bandgap semiconductors, which offer a high signal-to-noise ratio since they only response the ultraviolet emission in the flame. Diamond is a robust semiconductor with a wide-bandgap of 5.5 e V, exhibiting an intrinsic solar-blindness for deep-ultraviolet(DUV) detection. In this work, by using a submicron thick boron-doped diamond epilayer grown on a type-Ib diamond substrate, a Schottky photodiode device structure- based flame sensor is demonstrated. The photodiode exhibits extremely low dark current in both forward and reverse modes due to the holes depletion in the epilayer. The photodiode has a photoconductivity gain larger than 100 and a threshold wavelength of 330 nm in the forward bias mode. CO and OH emission bands with wavelengths shorter than 330 nm in a flame light are detected at a forward voltage of-10 V. An alcohol lamp flame in the distance of 250 mm is directly detected without a focusing lens of flame light.

Determination of band alignment between GaO_(x)and boron doped diamond for a selective-area-doped termination structure

An n-GaO_(x)thin film is deposited on a single-crystal boron-doped diamond by RF magnetron sputtering to form the pn heterojunction.The n-Ga Ox thin film presents a small surface roughness and a large optical band gap of 4.85 e V.In addition,the band alignment is measured using x-ray photoelectron spectroscopy to evaluate the heterojunction properties.The GaO_(x)/diamond heterojunction shows a type-Ⅱstaggered band configuration,where the valence and conduction band offsets are 1.28 e V and 1.93 e V,respectively.These results confirm the feasibility of the use of n-GaO_(x)as a termination structure for diamond power devices.

Integration of 3D interconnected porous microstructure and high electrochemical property for boron-doped diamond by facile strategy

Three-dimensional(3D)porous boron-doped diamond(BDD)flm is an attractive electrode material but tough to synthesize.Herein,the 3D porous BDD flms were constructed in a facile and template-free way.The BDD/non-diamond carbon(NDC)composite flms were frstly fabricated by hot flament chemical vapor deposition(HFCVD)technique,and then the porous BDD flms with 3D interconnected porous microstructure,different pore size and NDC-free diamond were achieved by selective removal of NDC.It is manifested that higher electrochemical response,large double layer capacitance(17.54 m F/cm^(2))in diamond electrodes,wide electrochemical window of 2.6 V and superior long-term stability were achieved for 3D porous BDD flm.This derives from the synergistic effect of microstructure and phase composition of the porous flms.3D interconnected structure possesses prominent improvement of effective surface area and accessible porous channel,signifcantly enhancing the species adsorption and mass transfer.The3D porous BDD flms,composed of NDC-free diamond,exhibit excellent structural stability and corrosion resistance,which favor the enhancement of long-term stability and water splitting overpotential.The facile fabricating approach and excellent structure/electrochemical character demonstrate the appealing application in many electrochemical felds for 3D porous BDD flms,such as energy storage and conversion,wastewater treatment and purifcation.

Direct and Simultaneous Determination of Phenol, Hydroquinone and Nitrophenol at Boron-Doped Diamond Film Electrode

The electrochemical characteristics of multi-component phenolic pollutants, such as phenol （Ph）, hydroquinone （HQ） and 4-nitrophenol （4-NP）, were investigated on boron-doped diamond （BDD） film electrode by differential pulse voltammetry （DPV） technique. A simple and feasible platform was accordingly established for the direct and simultaneous determination of these three phenolic pollutants. Results showed that, Ph, HQ and 4-NP gave obvious oxidation peaks on BDD electrode at the potential of 1.24, 0.76 and 1.52 V, respectively. Each of them displayed good linear relationship between their oxidation peak currents and their corresponding concentrations in a rather wide range coexisting with one or two of the other phenolic pollutants. The detection limits of Ph, HQ and 4-NP were estimated to be as low as 1.82×10^-6, 1.67×10^-6 and 1.44×10^-6 mol·L^-1, respectively. Therefore, a promising direct and simultaneous electrochemical determination method of multi-component phenolic pollutants in wastewater samples was constructed successfully on BDD electrode with advantages being rapid, simple, convenient, sensitive, in situ and inexpensive.

Electrochemical reduction of CO_2 and degradation of KHP on boron-doped diamond electrodes in a simultaneous and enhanced process

In this research a novel electrochemical system using dual boron-doped diamond (BDD) electrodes as the anode and cathode, for the first time, has been developed for CO_2 conversion and wastewater treatment in a synergetic and simultaneous process. On the BDD cathode CO_2 is converted into formaldehyde while in the anodic side organic wastes are decomposed on the BDD anode. Interestingly, when potassium hydrogen phthalate (KHP) was used as the organic model to be degraded in the anodic side, a higher efficiency of formaldehyde generation from CO_2 was observed on the BDD cathode. The enhanced effect of formaldehyde formation in the presence of KHP oxidation suggests that this novel electrochemical system can combine conversion of CO_2 to the form of high-value chemicals and wastewater purification in a simultaneous and harmonious process.

Effect of oxygen terminated surface of boron-doped diamond thin-film electrode on seawater salinity sensing

Tremendous demands for highly sensitive and stable seawater salinometers have motivated intensive research on advanced electrode materials.Boron-doped diamond(BDD)is attractive in terms of its high mechanical stability and chemical inertness,but is usually hindered by its low double-layer capacitance(C_(dl))for seawater salinity detection.Here,inspired by the principle of oxygen-terminated BDD electrode endowing higher C_(dl)than hydrogen-terminated surface,we introduce the oxygen terminated surface by oxygen plasma or reactive ion etch(RIE),and the fabricated oxygen terminated BDD electrodes demonstrate high sensitivity and long-term stability in seawater salinity detection comparing with the hydrogen terminated BDD electrodes.Significantly,the as-fabricated O-BDD-RIE electrodes not only show remarkable enhanced response even better than the commercial platinum black electrodes but also display long-time stability which is weekly verified by continuous monitor for 90 days.The outstanding performance of the oxygen terminated BDD electrodes can be ascribed to the enhancement of C-O surface functional group on C_(dl).In addition,a comprehensive analysis of effective electroactive surface area(EASA)and C_(dl)proves that the surface oxygen is the major factor for the improved C_(dl).In summary,the excellent oxygen terminated BDD electrodes promise potential application in seawater salinity detection.

纳米金刚石掺混纳米氧化锌的场发射特性

利用水热法制备了菊花状的氧化锌纳米棒,并进行表征,将纳米氧化锌掺入纳米金刚石中配制成电泳液,超声分散后电泳沉积到钛衬底上,再经热处理后进行场发射特性的测试.结果表明：未掺混的金刚石阴极样品的开启电场为7.3V/μm,在20V/μm的电场下,场发射电流密度为81μA/cm2;掺混后阴极样品的场发射开启电场降低到4.7-6.0V/μm,在20V/μm电场下,场发射电流密度提高到140-158μA/cm2.原因是纳米ZnO掺入后,增强了涂层的电子输运能力、增加了有效发射体数目,提高了场增强因子β,而金刚石保证了热处理后涂层与衬底的良好键合,形成了欧姆接触,降低了场发射电流的热效应.场发射电流的稳定性随掺混ZnO量的增加而下降,要兼顾场发射电流密度及其稳定性,适量掺入ZnO可有效提高纳米金刚石的场发射性能.

氧化锌纳米棒阵列/p型金刚石异质结的制备及其光催化性能

本文通过水热法在硼掺杂金刚石膜上制备了ZnO纳米棒阵列,并采用X射线衍射仪(XRD)、Raman光谱、扫描电子显微镜(SEM)等手段对样品的形貌和结构进行表征。电学性能测试结果表明,ZnO纳米棒阵列/p型金刚石异质结具有很好的整流特性。光催化性能研究结果表明,ZnO纳米棒阵列与p型金刚石之间形成的异质结效应使ZnO纳米棒阵列/p型金刚石异质结光催化剂具有良好的光催化性能,在紫外光照射下,其对甲基橙的降解率达到73%。

掺硼金刚石纳米棒电极的制备及电化学性质

引言掺硼金刚石(BDD)薄膜具有宽的电势窗口、低的背景电流、高的化学和物理稳定性、良好的生物兼容性等优点,因此在电化学检测、废水处理以及微电子器件等领域得到了很好的应用。目前。

硼掺杂金刚石纳米棒电极对比阿培南的电化学检测研究

在自制的硅纳米线上采用热丝化学气相沉积方法制备了硼掺杂金刚石纳米棒电极。采用循环伏安及计时电流方法测定了在磷酸缓冲溶液中的药物比阿培南的浓度,灵敏度达到0.038μAμM-1较相同条件下制备得到的普通硼掺杂金刚石电极(0.028μAμM-1)相比有所提高。该纳米棒电极由于特殊的表面形貌,较普通硼掺杂金刚石电极表现出更优异的电化学检测性能。

纳米金刚石表面择优取向生长的氧化锌纳米棒阵列制备及在DNA检测中的应用

研制了基于氧化锌纳米棒阵列的高稳定性和高特异性DNA荧光传感器．首先在纳米金刚石表面制备一层择优取向生长的氧化锌纳米棒，然后通过共缩聚方法在氧化锌表面修饰一层带氨基的硅层．用SEM和XPS对其进行了表征．通过非共价键或共价键方式把探针DNA固定在氧化锌和氨基修饰的氧化锌表面．并对荧光标记DNA进行了检测。实验结果表明共价固定方法比非共价固定方法有更好的特异性。此外，共价固定方法有好的稳定性和较高的灵敏度．

金刚石膜表面ZnO纳米棒制备及场发射性能研究

以硝酸锌为原料,乌洛托品为催化剂,采用水热法分别在自支撑金刚石膜及硅基底上制备了ZnO纳米棒。采用场发射扫描电子显微镜、X射线衍射、拉曼光谱、PL谱、场发射测试表征了ZnO纳米棒/硅及ZnO纳米棒/自支撑金刚石膜的形貌、尺寸及场发射性能。结果表明,在两种基底上制备的ZnO纳米棒均沿c轴方向生长,其中在自支撑金刚石膜上制备的ZnO纳米棒出现了尖端现象,并且具有更好的结晶度、纯度与更少的结构缺陷,其开启电场为6.8 V/μm,在11.9 V/μm的电场下,发射电流密度为0.20 m A/cm^2,场增强因子比在Si基底上制备的ZnO纳米棒的场发射性能高11.5倍。