Phenol degradation by anodic oxidation on boron-doped diamond electrode combining TiO_2 Photocatalysis

Boron-doped diamond （BDD） electrocatalysis is combined with photocatalysis using titanium dioxide （TiO2） as a catalyst to improve pollutant-oxidation efficiency. Phenol solution is chosen as model wastewater. Different methods involving BDD and/or TiO2 during the degradation processes are compared. Parameters such as the currency density and initial concentration are varied in order to determine their effects on the oxidation process. Moreover, the degradation kinetics of phenol is experimentally studied. The results reveal the superiority of series combination of BDD and TiO2, especially the treatment process of electrocatalysis and succedent photocatalysis, and the optimum working currency density for electrocatalysis is 25.48 mA/cm2. The removal rate decreases with the increase in the initial phenol concentration and the degradation reaction follows quasi-first-order kinetics equation.

Electrochemical oxidation of reactive brilliant orange X-GN dye on boron-doped diamond anode

In this study,the electrochemical oxidation of reactive brilliant orange X-GN dye with a boron-doped diamond(BDD)anode was investigated.The BDD electrodes were deposited on the niobium(Nb)substrates by the hot filament chemical vapor deposition method.The effects of processing parameters,such as film thickness,current density,supporting electrolyte concentration,initial solution pH,solution temperature,and initial dye concentration,were evaluated following the variation in the degradation efficiency.The microstructure and the electrochemical property of BDD were characterized by scanning electron microscopy,Raman spectroscopy,and electrochemical workstation;and the degradation of X-GN was estimated using UV-Vis spectrophotometry.Further,the results indicated that the film thickness of BDD had a significant impact on the electrolysis of X-GN.After 3 h of treatment,100%color and 63.2%total organic carbon removal was achieved under optimized experimental conditions:current density of 100 mA/cm2,supporting electrolyte concentration of 0.05 mol/L,initial solution pH 3.08,and solution temperature of 60°C.

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.

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.

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.

Electrolytic Production of NF3 Using Boron-Doped Diamond Anode in Molten NH4F·2HF

The current efficiency for NF3 formation was independent on the current density in the range of 200 to 1,000 mA·cm^2. The average values of NF3 current efficiencies on the BDD （boron-doped diamond） anode with the boron-concentration of 2,500 ppm were 32.3% at 80℃, 63.3% at 100℃ and 59.7% at 120℃. The best current efficiencies for NF3 formation on the BDD anode with boron-concentrations of 2,500, 5,000 and 7,500 ppm were obtained at 100℃ and those were 63.3%, 73.3% and 56.2%, respectively. Although anode effect occurred on the BDD electrodes covered with a part of the surface of the spiculate structure, which had the boron-concentrations higher than 7,500 ppm, it did not take place on the BDD electrodes covered with the surface of diamond structure, even if the BDD electrode had the boron-concentration of 8,000 ppm.

BDD电极电化学氧化清洗工艺氧化性研究

为了改进现有的RCA清洗法以及臭氧/过氧化氢湿式清洗技术,利用金刚石膜(BDD)电极的高级电化学氧化技术生成过氧化物氧化有机物,以实现简化清洗设备及节能环保。为研究金刚石膜电极的氧化能力,电解不同浓度的硫酸钾溶液,通过高锰酸钾滴定法进行氧化性的测量,研究原料浓度对生成过氧硫酸盐浓度的影响;通过添加KOH调节pH值,研究pH值对电化学制备过氧化物的影响,用该电化学氧化方法与RCA清洗法进行清洗效果对比。实验结果显示,金刚石膜电化学氧化能力可以通过阳极电解液浓度以及pH值的调整得到控制,清洗效果在Si片表面粗糙度方面明显优于传统的RCA清洗法,而且更加节能环保。

电压和电极间距对BDD电极电化学氧化效率的影响

掺硼金刚石（BDD）薄膜电极具有很宽的电势窗口、很小的背景电流、很高的电化学稳定性、其电化学响应在很长时间内保持稳定以及耐腐蚀等优点。采用热丝化学气相沉积（HF—CvD）方法制备掺硼金刚石薄膜，并用金相显微镜、原子力显微镜（AFM）、X射线衍射（XRD）这三种测试方式进行表征。BDD薄膜电极在电解过程中消耗很多能量。从提高氧化效率来降低能耗的角度出发，研究了电压及电极间距对BDD薄膜电极电化学氧化效率的影响。通过实验得出电压在5～13V时电化学氧化效率会随着电压的升高而升高；电极间距在0．5～4cm时电化学氧化效率随着电极间距的增大而降低。

碳源体积分数对BDD薄膜制备和性能的影响

以丙酮为碳源,采用热丝化学气相沉积(HFCVD)技术在钽衬底上制备p型硼掺杂金刚石(BDD)薄膜电极。在BDD电极制备过程中,碳源体积分数对它的质量和性能影响很大。利用AFM和XRD分析了丙酮体积分数对BDD电极表面形态和成膜质量的影响。利用循环伏安法研究了采用不同体积分数的丙酮沉积的BDD电极对电化学窗口和背景电流的影响。分别采用BDD电极和不锈钢片作阳极和阴极电解K2SO4溶液,并利用KMnO4滴定法检测BDD电极的氧化效率。结果表明,优化丙酮体积分数可以提高BDD的均匀性和附着力。合适的丙酮体积分数所制备的BDD电极具有电化学窗口宽、背景电流低和电极氧化效率高等特点,有很好的应用前景。

不同基底BDD电极对模拟染料废水的降解脱色试验

在Si、Ta、SiC、Ti四种不同的基底上通过热丝化学气相沉积法分别生长了掺硼金刚石(BDD)薄膜。试验对BDD膜层的微观形貌、电极的电化学性能进行了研究。四种基底的BDD电极均具有较宽的电位窗口;Ta-BDD和SiC-BDD晶体形貌完整;Ta-BDD和Ti-BDD具有较好的膜基附着力,具有较长的寿命。试验表明,使用12 h后,Ta-BDD与Ti-BDD仍具有良好的电解性能,微观形貌完整,而Si-BDD和SiC-BDD分别使用4h和6 h后,膜层便开始脱落。试验测定了Ta-BDD电极对活性艳红X-3B模拟染料废水的降解脱色效果,考察了不同条件(槽电压、电解质浓度、电解质种类及pH)对脱色效果的影响。结果表明:在酸性介质中,当硫酸钠浓度为2.5 g/L时,经过120 min电解,模拟废水中的染料可脱除至1%以下。NaCl作为支持电解质时,相比于Na2SO4对废水色度的脱除具有更强的作用。

温度对n-ZnO/p-diamond薄膜异质结器件制备和电学性质的影响

采用反应磁控溅射法在p型硼掺杂金刚石(BDD)薄膜衬底上制备了非有意掺杂n型氧化锌(ZnO)薄膜。利用XRD、SEM、I-V特性曲线对n-ZnO/p-BDD薄膜复合结构进行表征分析。n-ZnO多晶膜沉积在p-BDD膜上形成了具有良好整流特性的异质结。在空气中对异质结进行退火处理,研究了退火(400℃,700℃)对异质结性质的影响。实验表明,较高退火温度处理,可获得多取向的ZnO膜,晶粒尺寸增大,n-ZnO/p-BDD异质结开启电压减小。不同温度下的电学性质测量结果证明该异质结适合在高温环境下工作。

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.

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.

掺硼金刚石薄膜电极的制备及电化学特性

通过热丝化学气相沉积(HFCVD)技术,在钽衬底上制备了p型掺硼金刚石(BDD)薄膜电极。利用原子力显微镜(AFM)分析丙酮体积分数对BDD电极的表面形貌和成膜质量的影响,利用循环伏安法(CV)分析BDD电极在不同种类、不同浓度电解液中的电化学特性。结果表明,当丙酮体积分数为1.5%时,金刚石薄膜表现出优异的附着力,并且BDD电极具有稳定的电化学特性。采用制备的BDD电极,在不同浓度的KCl和KH2PO4电解液中使用,得出电势窗口均在3.4 V以上。

原位铋修饰掺硼金刚石电极检测分析锌离子

以原位铋修饰掺硼金刚石(BDD)电极为传感电极对锌离子进行检测分析,方法迅速、简便、绿色环保。相对裸电极原位铋修饰BDD电极,锌离子响应电流信号有较大提高。考察了扫描方式、铋离子浓度、电极硼掺杂浓度对锌离子传感分析的影响,优化了传感分析中脉冲频率和尺寸、支持电解液p H值、沉积电位、沉积时间等参数。锌离子浓度与溶出峰电流值在50~300μg/L范围内呈线性关系,相关系数为0.997 9,检出限为2.32μg/L。电极表现出较好的重复性。常见离子除铜离子对锌离子测定有很大干扰外,其他离子干扰相对较小。

碳薄膜电极材料在电分析化学中的应用

由于具有一系列的优点,碳材料被广泛应用于电分析化学。新型碳电极材料的开发及其性质研究对电分析化学的发展起着重要的推动作用。最近报道了一些制备新型碳薄膜电极材料的方法,因为制备方法不同,这些碳薄膜材料的电化学性质如电位窗、稳定性、导电性也存在显著的差异。目前电位窗宽、背景电流低、稳定性高、表面不易被电极产物钝化的碳薄膜电极材料的研究非常活跃。本文综述了采用不同方法制备的一些碳薄膜电极材料如硼掺杂的金刚石薄膜、无定形碳和纳米晶体碳薄膜材料等在电分析化学中应用。

掺硼多晶金刚石膜电极的电化学研究

通过MPCVD法在高掺杂硅衬底上生长掺硼金刚石膜（BDD）,并用四探针,扫描电镜,激光拉曼,电化学工作站对其进行了检测,发现所制备的掺硼金刚石膜电导率达10-2Ω.cm,同时发现金刚石膜质量因硼原子的掺入而有所下降,采用循环伏安法研究其电化学性质,结果表明,与Pt电极相比（1.8V和-1×10-3~3×10-4A）,BDD具有很宽的电化学窗口（~3.2 V）,较低的背景电流（-3×10-6~2×10-6A）,在铁氰化钾电解液中,表面所进行的电化学反应具有较好的准可逆性,在对有机物苯酚的催化氧化检测中发现：与Pt电极相比,BDD电极氧化能力强,且氧化产物简单、彻底,因此可以作为一种理想的电极材料.

硼掺杂浓度对金刚石薄膜电极的影响

金刚石由于其独特的物理和化学性质,使其成为电极材料的首选。通过热丝化学气相沉积(HFCVD)技术,在钽片上制备了p型掺硼金刚石(BDD)薄膜电极。通过掺入硼元素在金刚石带隙间引入杂质能级,改变了电极的电学特性,同时硼替位碳原子改变了金刚石的结构。通过原子力显微镜(AFM)和循环伏安法(CV)分析讨论了硼掺杂浓度对BDD电极的表面形貌和电化学特性的影响。结果表明,优化硼掺杂浓度可以使薄膜有好的致密性和稳定的电化学性质。硼掺杂浓度优化后制备的BDD电极电化学窗口可达3.8 V。

L-丝氨酸修饰掺硼金刚石薄膜电极检测去甲肾上腺素

采用直流等离子体喷射化学气相沉积（CVD）法制备了掺硼金刚石（BDD）薄膜电极。提出了应用L-丝氨酸修饰掺硼金刚石薄膜电极检测去甲肾上腺素,提高了去甲肾上腺素（NE）含量检测的精度。在浓度为2.0×10^-4mol/L的去甲肾上腺素溶液中,通过对比BDD裸电极与L-丝氨酸修饰BDD电极得出：经L-丝氨酸修饰的BDD电极的电催化氧化能力明显增强;在浓度为1.0×10^-4～1.0×10^-8mol/L的范围内,浓度的对数与氧化峰电流基本呈线性关系,且检测限为1.0×10^-9mol/L。

Surface treatment technology of downhole water cut sensor

Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well fluid erosion,electrochemical corrosion,and oil pollution during its long-term service in the downhole.A technology for electrode surface treatment is proposed using boron-doped diamond(BDD)films to improve the service performance of the modified electrode.The hot wire chemical vapor deposition method was adopted to fabricate BDD film,the boron doping concentration and deposition time were optimized,and fluorination treatment was applied to improve the wear resistance,electrochemical corrosion resistance,and oleophobic property of the BDD film comprehensively.The results showed that BDD film with boron doping concentration of 6×10^(-3) exhibited high wear resistance and good electrochemical corrosion resistance,and endowed the modified electrode with superior erosion resistance and corrosion resistance.The friction coefficient and wear rate of BDD modified electrode were 92%and 78%lower than those of Invar alloy,also,the low-frequency impedance modulus value of the modified electrode was higher than 1×10^(4) Ω·cm^(2).The BDD film prepared with a deposition time of 8 h had a favorable micro-nano structure owing to small grain size and uniform distribution.Such morphology was conducive to enhancing the oleophobic performance of the modified electrode,and its contact angle in the simulated well fluid was high to 102°.The engineering applicability of BDD film modified electrode under simulated working conditions indicated that,the modified electrode had excellent comprehensive performances of erosion resistance,electrochemical corrosion resistance and oil adhesion resistance,and can realize the long-term stable operation of the conductance water cut sensor under harsh downhole conditions.