三维氮掺杂石墨烯气凝胶负载钴酞菁作为高效的氧气还原反应催化剂

通过两步溶剂热法制备得到三维氮掺杂石墨烯与吡啶氧基钴酞菁的复合材料(CoTPPc/NGA).该复合材料具有优良的氧气还原性能,在起峰电位和半波上接近商业化的铂碳催化剂(Pt/C),且在稳定性和抗甲醇性能上优于铂碳催化剂,有望代替铂碳催化剂成为碱性直接甲醇燃料电池的阴极催化剂.     

NHPI结合磺化酞菁钴催化的乙苯氧化反应

探索了一种由N-羟基邻苯二甲酰亚胺（NHPI）和磺化酞菁钴（CoSPc）组成的催化体系催化的将乙苯转化成相应氧化物有效且温和的方法．结果显示控制NHPI和乙苯物质的量比为0．050,NHPI和CoSPc物质的量比为6,反应温度90℃,是该氧化反应的最佳条件,在此条件下,乙苯在氧气中反应10h,乙苯转化率和苯乙酮选择性分...     

Self‐Assembled Monolayers of Cobalt and Iron Phthalocyanine Complexes on Gold Electrodes: Comparative Surface Electrochemistry and Electrocatalytic Interaction with Thiols and Thiocyanate

The self‐assembling of the octa(hydroxyethylthio)‐metallophthalocyanine {MOHETPc (M=Co and Fe)} complexes and their similar analogues, octabutylthiometallophthalocyanine {MOBTPc (M=Co and Fe)} complexes on gold electrodes are investigated. Comparative surface voltammetric insights into their distinct self‐assembling properties with respect to the passivation of Faradaic processes and surface coverages, including their solution electrochemistry, suggest different orientations and non‐cleavage of their C? S bonds. In the pH 2?9 range, the reversible [M^(III)Pc(?2)]⁺ / [M^(II)Pc(?2)] redox couples show potential shifts close to ?59 mV / pH. The gold electrodes modified with the SAMs of these species show electrocatalytic activity towards the oxidation of thiols (L ‐cysteine, homocysteine and penicillamine) and thiocyanate in acidic media with detection limits in the region of 10^?7–10^?6 mol dm^?3. These monolayers are stable and easily reproducible.     

Electrocatalytic Behavior of Glassy Carbon Electrodes Modified with Multiwalled Carbon Nanotubes and Cobalt Phthalocyanine for Selective Analysis of Dopamine in Presence of Ascorbic Acid

This work describes the development, electrochemical characterization and utilization of a cobalt phthalocyanine modified carbon nanotube electrode for the quantitative determination of dopamine in 0.2 mol L^?1 phosphate buffer contaminated with high concentration of ascorbic acid. The electrode surface was analyzed by cyclic voltammetry and electrochemical impedance spectroscopy which showed a modified surface presenting a charge transfer resistance of 500 Ω, against the 16.46 kΩ value found for the bare glassy carbon surface. A pseudo rate constant value of 5.4×10^?4 cm s^?1 for dopamine oxidation was calculated. Voltammetric experiments showed a shift of the peak potential of DA oxidation to less positive value at 390 mV as compared with that of a bare GC electrode at 570 mV. The electrochemical determination of dopamine, in presence of ascorbic acid in concentrations up to 0.1 mol L^?1 by differential pulse voltammetry, yielded a detection limit as low as 2.56×10^?7 mol L^?1.     

四磺酸酞菁钴-DDAB表面活性剂薄膜电极的电化学与电化学催化研究

四磺酸酞菁钴配合物阴离子(CoPcTS_4-)在水溶液中可借助离子交换进入阳离子表面活性剂双十二烷基二甲基溴化铵(DDAB)薄膜,从而形成CoPcTS_4-DDAB薄膜电极.循环伏安法表明,该薄膜电极在pH7.0的空白缓冲溶液中十分稳定,有两对准可逆的还原氧化峰,其中第一对峰的E_pc1=-0.28V,E_pa1=-0.18V(vs.SCE),为中心离子Co(II)Co(I)的还原氧化峰;第二对峰的E_pc2=-1.30V,E_pa2=-1.18V,为酞菁环的还原氧化峰.应用循环伏安法估计了该薄膜体系的电荷传递扩散系数D_ct和表观非均相电极反应速率常数k^o'.CoPcTS_4-DDAB薄膜电极可用于对三氯乙酸(TCA)的电化学催化还原.催化电流与TCA浓度在4×10^-5～1×10^-3molL范围内成线性关系.     

Electrocatalytic Oxidation and Voltammetric Determination of Hydrazine in Industrial Boiler Feed Water Using a Cobalt Phthalocyanine-modified Electrode

Abstract

A carbon paste electrode modified with cobalt phthalocyanine (CPECoPc) was developed and applied to the determination of hydrazine [N₂H₄] in industrial boiler feed water. The CPECoPc exhibited good electrocatalytical activity for hydrazine oxidation at pH 13. A linear correlation was obtained between anodic peak current (I_ap) and hydrazine concentration in the range of 1.25 × 10^?4 to 9.80 × 10^?4 mol L^?1, fit by the equation I_ap = 1.47 + 4.90 × 10⁵ [N₂H₄] with a correlation coefficient of 0.9967. A detection limit of 7.35 × 10^?5 mol L^?1 was obtained. Recovery of hydrazine from three samples ranged between 99.0% and 102.9%. The modified electrode showed no interference by cations commonly present in boiler water, such as K⁺, Na⁺, Ca²⁺, Mg²⁺, Al³⁺, Pb²⁺, and Zn²⁺. The results obtained for hydrazine in boiler water using the proposed modified electrode are in agreement with the data obtained by a standard spectrophotometric method, at the 95% confidence level.     

棒状薄层色谱/氢火焰法分析磺化酞菁钴的组成

研究建立了一种采用棒状薄层色谱／氢火焰离子检测（TLC／FID）对磺化酞菁钴组成进行定性、定量分析的方法。用薄层色谱并结合质谱分析 表明工业磺化酞菁钴中含有一磺化酞菁钴的两种同分异构体,二磺化酞菁钴的5种同分异构体及三磺化酞菁钴;用棒状薄层色谱／氢离子火焰检测方法可以对磺化酞菁钴中各组分进行定量分析。该方法操作简便,测定时间短,灵敏度高,可用于磺化酞菁钴工业合成的产品质量控制。     

酞菁锌的电子光谱和三阶非线性光学性质

用ＩＮＤＯ／ＳＤＣＩ方法研究了酞菁锌的电子结构，紫外－可见光谱，三阶三线性光学系数及其色散效应。发现由于酞菁锌中Ｚｎ（Ⅱ）对γ的贡献很小使酞菁锌与酞菁的＜γ＞几乎相等。根据我们的计算结构对此进行了合理的解释。     

Electrochemical Detection of Nitrite Using an Asymmetrically Substituted Cobalt Phthalocyanine Conjugated to Metal Tungstate Nanoparticles

This paper explores the synthesis and characterisation of an asymmetrical Co phthalocyanine (CoPc), and its covalent linking to two tungsten nanoparticles: bismuth tungsten oxide (Bi₂WO₆) and nickel tungsten oxide (NiWO₄). The nanoparticles were also mixed with the CoPc. The CoPc, nanoparticles and their respective conjugates were used as electrocatalysts in the electrochemical detection of nitrite. The electrocatalysts studied in this work had sensitivities ranging from 3–133 μA/mM while the limits of detection (LoDs) ranged between 0.063 μM and 1.7 μM. Bi₂WO₆ and its conjugate exhibited better LoD than corresponding NiWO₄ and conjugate.     

双核钴锰酞菁对SOCl2还原反应的电催化性能

为了确定双核金属酞菁化合物对亚硫酰氯还原反应是否具有比单核金属酞菁更强的电催化性能, 通过循环伏安测试方法, 用酞菁钴和酞菁铁作为对比, 研究了双核钴锰酞菁在1.5 mol·L-1 LiAlCl4/SOCl2电解液中的电催化行为, 并计算出动力学参数, 由此来评估具有平面结构的双核金属酞菁化合物对亚硫酰氯还原的催化活性的影响. 通过比较循环伏安曲线发现, 与单核酞菁钴(II)和酞菁铁(II)相比, 双核钴锰酞菁对SOCl2还原反应具有更好的催化活性, 能提高SOCl2还原反应的交换速率常数和SOCl2在玻碳电极上的扩散系数, 从而提高SOCl2还原电位和电流.通过ER14250型实体电池10 mA放电性能测试验证表明, 与单核酞菁钴和酞菁铁催化剂的电池相比, 双核钴锰酞菁在低温(-30 ℃)下可提高放电中点电压0.3 V, 在常温(25 ℃)下可以提高放电容量约100 mAh, 催化效果比单核酞菁钴和酞菁铁显著.     

Cobalt Phthalocyanine Molecular Electrode for the Electrochemical Investigation of the Release of Glutathione upon Copper‐Catalyzed Decomposition of S‐Nitrosoglutathione

Decomposition of S‐nitrosoglutathione (GSNO) in phosphate buffer solution at physiological pH 7.4 in the presence of cuprous ion as a catalyst and sodium borohydride as a reducing agent is analyzed by observing the transient apparition of reduced glutathione GSH through its electrooxidation. Transient formation of GSH, upon decomposition of 1 mM GSNO in presence of 0.025 mM Cu(NO₃)₂ and 1 mM NaBH₄ was detected by using an ordinary pyrolytic graphite electrode modified with an adsorbed monolayer of cobalt phthalocyanine at 0 V vs. SCE.     

纳米四氧化三钴催化剂的制备及其电催化性能

四氧化三钴（Co3O4）作为一种重要的电极催化材料,具有催化活性高,价格低廉等特点,可有效解决过度依赖储量少,成本高的Pt系贵金属催化剂等问题。实验采用化学沉淀法结合热分解法,以Co(NO3)2·6H2O为钴源,沉淀剂为NH4HCO3,聚乙二醇（PEG）为表面活性剂,在45℃条件下反应,分别选择室温和水热环境陈化处理,洗涤干燥后,350 ℃的马弗炉里煅烧3 h,通过调控陈化场所和时间可制备出块状、球状及杆状的Co3O4,其中球状的最小粒径达8.54 nm,然后把制备出均相高纯度的Co3O4作为直接甲醇燃料电池阴极催化剂来测试电催化活性,结果显示Co3O4具有良好的电催化性能,在1 mol/L的KOH的氧化还原峰的电位1.34 V,比商用Pt/C(20 wt%)的高0.05 V。在氧气饱和的1 mol/L的KOH电介质溶液中加入20000 ppm的无水甲醇,250s后两种材料的电流密度衰减为0.0051 mA/cm2与0.0136 mA/cm2,半波电位分别为1.025 V和1.113 V,虽然Co3O4的催化活性不及Pt/C(20 wt%)材料,但对甲醇的耐受性及稳定性要优于商用Pt/C(20 wt%)材料。     

Effect of Visible Light on the Dimerization of Cobalt (II) Tetrasulfonated Phthalocyanine in Water

Abstract

Beelen and coworkers in the Netherlands recently reported that visible light enhanced the rate of selective oxidation of mercaptoethanol by dioxygen, catalyzed by cobalt (II) tetrasulfonated phthalocyanine (CoTSPC). The Dutch workers speculated that visible light promoted disaggregation of CoTSPC, producing more of the catalytically active monomer.

If Beelen and associates are correct, then it is possible that the values for the dimerization constants of CoTSPC are in error. since the values were measured spectrophotometrically in the region of the spectrum where Beelen contends visible light promtes disaggregation. To test whether the dimerization constants are altered by the spectrophotometer, the absorbance of a CoTSPC solution was measured with a diode array UV-VIS spectrophotometer. By comparing the spectrum of CoTSPC in the UV region with the tungsten lamp active and then inactive, one can see whether the visible light affects aggregation. It turned out that no change was observed in the spectrum of CoTSPC when the tungsten lamp was turned off, so the dimerization constants measured in the visible region of the spectrum are not affected by the spectrophotometer.     

Iodine‐Doped Cobalt Phthalocyanine Supported on Multiwalled Carbon Nanotubes for Electrocatalysis of Oxygen Reduction Reaction

4‐(4,6‐Diaminopyrimidin‐2‐ylthio) phthalocyaninatocobalt(II) (CoPyPc) was iodine doped, and its electrocatalytic properties explored. Physical characterization techniques such as UV‐vis, X‐ray photoelectron, electron paramagnetic resonance and infra‐red spectroscopy were used. Cyclic voltammetry, electrochemical impedance spectroscopy and rotating disk electrode were used for electrochemical characterization of electrodes modified with the prepared phthalocyanine and its nanocomposites. The electrocatalytic effect of a new iodine‐doped cobalt phthalocyanine derivative supported on multiwalled carbon nanotubes was then investigated towards oxygen reduction reaction. The electrocatalytic activity of the iodine‐doped cobalt phthalocyanine was found to be superior in terms of current over the undoped phthalocyanine nanocomposite.     

电化学催化剂CoPc对Ni-MH电池浮充性能的影响

针对Ni-MH电池充电过程中氧的产生和不恰当的消除方式带来的内压升高和热量聚积使电池总体性能衰减很快的问题, 提出采用降低化学催化氧还原的比例, 而提高热量产生少的电催化氧还原比例的方法加以解决. 研究了电化学催化剂CoPc(酞菁钴)对Ni-MH电池浮充性能的影响. 实验结果表明采用合适的方式添加CoPc的电池具有较好的浮充性能. 其中在电解液中添加CoPc的电池具有最好的充电效率和循环能力; 2000次浮充以后其内压升高速度也最低.     

Characterization and Electrocatalytic Activity of Nanocomposites Consisting of Nanosized Cobalt Tetraaminophenoxy Phthalocyanine,Multi‐walled Carbon Nanotubes and Gold Nanoparticles

Glassy carbon electrodes were modified with composites containing cobalt tetraaminophenoxy phthalocyanine nanoparticles (CoTAPhPc NP ), multi‐walled carbon nanotubes (MWCNT) and gold nanorods (AuNRs). The modified electrodes were studied for their electrocatalytic behavior towards the reduction of hydrogen peroxide. Phthalocyanine nanoparticles significantly improved electron transfer kinetics as compared to phthalocyanines which are not in the nanoparticle form when alone or in the presence of multiwalled carbon nanotubes (MWCNTs). CoTAPhPc NP ‐MWCNT‐GCE proved to be suitable for hydrogen peroxide detection with a catalytic rate constant of 3.45×10³ M^?1 s^?1 and a detection limit of 1.61×10^?7 M. Adsorption Gibbs free energy ΔG^o was found to be ?19.22 kJ mol^?1 for CoTAPhPc NP ‐MWCNT‐GCE.     

酞菁钴催化剂载体表面含氮官能团对其在燃料电池中氧还原性能的影响

以酞菁钴为催化剂,纳米碳管为载体,分别通过超声法和四氢呋喃法混合分散,并在氮气氛围高温热处理制备了两种酞菁钴催化剂.热重分析（TGA）结果显示超声法制备的酞菁钴催化剂（CoPc-CNT-S）含钴的质量分数为8.1 wt%,四氢呋喃混合法制备的酞菁钴催化剂（CoPc-CNT-R）含钴的质量分数为7.0 wt%.X射线光电子谱（XPS）结果显示CoPc-CNT-R催化剂的含氮量是CoPc-CNT-S催化剂的两倍多,且两种催化剂含氮官能团的种类及比例不同.相比较而言,CoPc-CNT-S表面有更多的吡咯型氮.将两种催化剂应用于混合酸碱燃料电池中发现：CoPc-CNT-S对电催化氧还原有较高的活性和稳定性,将CoPc-CNT-S作为燃料电池的阴极催化剂分别工作5 h和15 h后,电荷转移电阻相对CoPc-CNT-R为阴极催化剂时均较低.原因可能是相近比例的吡啶型N和吡咯型N的协同作用有利于电催化氧还原.     

Determination of α‐Lipoic acid on a Pyrolytic Graphite Electrode Modified with Cobalt Phthalocyanine

In this work voltammetric techniques were explored for quantification of α‐Lipoic acid (ALA) using a pyrolytic graphite electrode modified with cobalt phthalocyanine. Cyclic voltammograms recorded in phosphate buffer solution containing 1×10^?3 mol L^?1 of ALA presented an oxidation peak located at +0.8 V vs. SCE. The modification of the electrode produced a 100 mV shift of the onset oxidation potential to less positive value and a substantial increase in the ALA oxidation current. Among the voltammetric techniques explored, differential pulse voltammetry showed the best performance for quantifications of the analyte in low concentrations. Limits of detection and quantification of ALA obtained corresponds to 3.4×10^?9 mol L^?1 and 1.2×10^?8 mol L^?1, respectively.     

Dopant-Induced Electronic States Regulation Boosting Electroreduction of Dilute Nitrate to Ammonium

Electrochemically converting NO₃⁻ into NH₃ offers a promising route for water treatment. Nevertheless, electroreduction of dilute NO₃⁻ is still suffering from low activity and/or selectivity. Herein, B as a modifier was introduced to tune electronic states of Cu and further regulate the performance of electrochemical NO₃⁻ reduction reaction (NO₃RR) with dilute NO₃⁻ concentration (≤100 ppm NO₃⁻−N). Notably, a linear relationship was established by plotting NH₃ yield vs. the oxidation state of Cu, indicating that the increase of Cu⁺ content leads to an enhanced NO₃⁻-to-NH₃ conversion activity. Under a low NO₃⁻−N concentration of 100 ppm, the optimal Cu(B) catalyst displays a 100 % NO₃⁻-to-NH₃ conversion at −0.55 to −0.6 V vs. RHE, and a record-high NH₃ yield of 309 mmol h⁻¹ g_cat⁻¹, which is more than 25 times compared with the pristine Cu nanoparticles (12 mmol h⁻¹ g_cat⁻¹). This research provides an effective method for conversion of dilute NO₃⁻ to NH₃, which has certain guiding significance for the efficient and green conversion of wastewater in the future.     

Determination of an Ethylene Bisdithiocarbamate Based Pesticide (Nabam) by Cobalt Phthalocyanine Modified Carbon Ink Electrode

A phthalocyanine based sensor, for anodic detection of sodium ethylene bisdithiocarbamate (Nabam) by coating a mixture of cobalt phthalocyanine (CoPC) modified carbon ink on the surface of a glassy carbon electrode, has been described. The modified ink was prepared by mixing three percent of cobalt phthalocyanine into carbon ink and then diluting the mixture with cyclohexanone in w/w ratio of 1/9. A suitable portion (or 1 μL) of ink mixture was then dip‐coated on a rotating disk glassy carbon electrode. The modified ink electrode was air‐dried for 15 mins before use. In comparison to the bare ink electrode on which the oxidation of Nabam takes place at 300 mV (vs. 3 M Ag/AgCl), the oxidation potential (?125 mV) of Nabam at the CoPC modified ink decreases significantly. A typical calibration plot of Nabam proportionally increases over the concentration range of 2.5 to 36 μM (R=0.9990). The detection limit is estimated about 28.8 nM (S/N=3) and its response time (between 10% to 90% of steady‐state response) is about 5.3 s at the injection of 5 μM Nabam. The sensitivity requirement of JMPR meeting (Joint FAO/WHO Meeting on Pesticide Residues) for ethylene bisdithiocarbamates (EBDCs) is achieved by this proposed scheme.