Study on the chemical synthesis and the performance of V（III）-V（IV） electrolyte

钒电池是一种高效储能装置,钒电池电解液直接影响电池性能。本文以V2O3、V2O5和H2SO4为原料,化学合成了用于钒电池的V（Ⅲ）-V（Ⅳ）电解液,研究了无水乙醇与焦磷酸钠作为添加剂对电解液稳定性和电化学活性的影响。实验结果表明,当V2O3/V2O5质量比为7.2∶1时,可以得到V（Ⅲ）/V（Ⅳ）离子浓度比为1.0的电解液;添加剂的加入能提高电解液的稳定性和电化学反应活性。     

酸碱催化剂浓度对柔性硅气凝胶性能和结构的影响

以甲基三甲氧基硅烷(MTMS)和正硅酸乙酯(TEOS)作为混合硅源,甲醇为溶剂,十六烷基三甲基溴化铵(CTAB)为表面活性剂,通过酸碱两步催化溶胶凝胶法制备醇凝胶,经超临界干燥可以制备高弹性疏水块状硅气凝胶。分别采用0.1 mol·L^-1 和0.01 mol·L^-1 的草酸作为酸催化剂,5 mol·L^-1 和10 mol·L^-1 的氨水作为碱催化剂,研究不同酸碱催化剂浓度对其网络结构的影响。发现高浓度酸和高浓度碱以及低浓度酸和低浓度碱作为催化剂合成的硅气凝胶的网络结构更加均匀,孔径分布更窄。其中,在草酸浓度为0.01 mol·L^-1、氨水浓度为5mol·L^-1 时,所得硅气凝胶密度为0.135 g·cm^-3、比表面积为807 m²·g^-1、孔隙率约为93%,凝胶最大可压缩至其起始长度的60%,压缩回弹率为100%。     

锌-空气电池电解液Zn2+浓度对析氢过程的影响

水溶液体系的二次金属-空气电池通常具有安全环保的特点,但是充电过程中仍然存在析氢副反应的安全隐患。使用线性电势扫描方法、Tafel极化曲线及极限扩散电流密度参数定量分析了二次锌-空气电池体系电解液中Zn²⁺浓度对析氢反应过程的影响。结果表明,随着电解液中Zn²⁺浓度的提高,析氢过电势逐渐增大,Zn²⁺浓度在6 mol·L^-1 KOH溶液中达到0.4 mol·L^-1时,析氢过电势超过2.42 V,析氢过电势比空白溶液提高1.2 V,并且Tafel极化曲线的截距超过1.5 V,析氢电势达到超高过电势范围。此外,由Zn²⁺提供的极限扩散电流密度提高至8.9 A·cm^-2,所对应的过电势提高700 mV。研究结果对于确立二次锌-空气电池极限充电范围提供定量依据,对电池安全平稳运行具有重要价值。     

V(Ⅲ)-V(Ⅳ)电解液的化学合成及性能

钒电池是一种高效储能装置,钒电池电解液直接影响电池性能。本文以V2O3、V2O5和H2SO4为原料,化学合成了用于钒电池的V(Ⅲ)-V(Ⅳ)电解液,研究了无水乙醇与焦磷酸钠作为添加剂对电解液稳定性和电化学活性的影响。实验结果表明,当V2O3/V2O5质量比为7.2∶1时,可以得到V(Ⅲ)/V(Ⅳ)离子浓度比为1.0的电解液;添加剂的加入能提高电解液的稳定性和电化学反应活性。     

锂-空气电池的高性能空气电极的性能研究

锂-空气电池是比能量最高的二次电池,已成为当今化学电源领域的研究热点。在锂-空气电池的各个组件中,空气电极的设计和制备是进一步提高锂-空气电池性能的关键。以简单的合成方法制备了一种具有高催化活性的镍酸镧（LaNiO₃）催化剂,利用Super P作为催化剂载体制备了一种新型空气电极。实验结果表明,含有LaNiO₃催化剂的锂-空气电池具有良好的充放电性能,放电电压平台为2.59 V,放电容量达到1 109 mAh·g^-1。比较了2种碳材料（Super P和GNS）作为催化剂载体的空气电极对电池充放电性能的影响,发现多孔性的空气电极结构更有利于电池性能的提高。此外,还分析了控制电解液（1 mol·L^-1 LiTFSI/TEGDME）中水含量的必要性。由Super P、LaNiO₃及水含量小于1×10^-5的电解液（1 mol·L^-1 LiTFSI/TEGDME）组装成的锂-空气电池具有良好的循环性能,循环第五圈的容量保持率为96.21%,且不出现电压平台的明显变化。     

Study on the chemical synthesis and the performance of V(Ⅲ)-V(Ⅳ) electrolyte

钒电池是一种高效储能装置,钒电池电解液直接影响电池性能。本文以V2O3、V2O5和H2SO4为原料,化学合成了用于钒电池的V(Ⅲ)-V(Ⅳ)电解液,研究了无水乙醇与焦磷酸钠作为添加剂对电解液稳定性和电化学活性的影响。实验结果表明,当V2O3/V2O5质量比为7.2∶1时,可以得到V(Ⅲ)/V(Ⅳ)离子浓度比为1.0的电解液;添加剂的加入能提高电解液的稳定性和电化学反应活性。     

锑离子添加剂对低共熔溶剂(DES)电解液液流电池的性能改善研究

非水系氧化还原液流电池（NARFB）的广泛应用受制于其较低的性能。在电解液中加入一些金属离子添加剂是一种可能的解决方案。实验研究了Sb³⁺离子对低共熔溶剂（DES）电解液液流电池电化学性能的影响。结果表明,添加Sb³⁺离子可以强化V（Ⅲ）/V（Ⅱ）氧化还原离子对的电化学反应动力学（最高可达22.6％）过程,钒离子在DES中的扩散系数提高了63.3％,并且电荷转移电阻降低了11.9％。场发射扫描电子显微镜表明,Sb³⁺离子电沉积在石墨毡的表面,对电化学反应起催化作用,从而改善了电化学性能。考虑增强的动力学和降低的活性比表面积之间的平衡,确定了Sb³⁺的最佳浓度为15 mmol·L^-1。此外,当使用含有Sb³⁺的负极电解液液流电池时,液流电池的功率密度提高了31.2%,从含原始电解质的3.08 mW·cm^-2到含15 mmol·L^-1 Sb³⁺离子的4.04 mW·cm^-2。这些结果为改善NARFB的电池性能提供了一个便捷而有前景的方法。     

复合添加剂对钒电池正极电解液性能的影响

为了提高钒电池电解液的性能，选取了3种复合添加剂，研究了复合添加剂对钒电池正极电解液稳定性和电化学性能的影响。利用电化学方法制备了2 mol/L的全钒液流电池正极5价钒离子电解液，采用临界胶束浓度法得到复合添加剂的配比为：1% KHSO₄+3 mmol/L SDBS（十二烷基苯磺酸钠）、1% KHSO₄+2 mmol/L D-山梨醇、1% KHSO₄+2 mmol/L CTAB（十六烷基三甲基溴化铵），并考察添加剂加入电解液后的稳定性与电化学性能。通过XRD分析手段，对电解液沉淀物的成分进行了表征。研究表明：添加剂的加入，并不会引起钒离子价态的变化，1% KHSO₄+2 mmol/L CTAB加入后，电解液峰电位差减小12 mV，峰电流增加9.8 mA，说明CTAB与KHSO₄在合适配比下，能够有效提高正极电解液的稳定性及可逆性，添加剂的引入并未引起电解液沉淀物的物相组成变化，电解液性能显著提高。     

锌催化电还原脱氯合成2,3,5,6-四氯吡啶:反应机理和工艺优化

采用循环伏安法和恒电位电解法,探讨了含有ZnCl₂的乙睛水混合溶液中五氯吡啶(PCP)在不锈钢阴极表面电还原脱氯生成2,3,5,6-四氯吡啶(2,3,5,6-TCP)的反应机理;采用恒电流电解法对该电还原脱氯过程的各种工艺条件进行了优化。结果表明:该体系中PCP电还原脱氯生成2,3,5,6-TCP主要遵循以Zn/Zn²⁺为氧化还原媒介的间接电还原机理;优化工艺条件下(阴极液含0.025mol·L^-1HCl+15%(体积分数)水+0.2mol·L^-1苯磺酸钠+0.16mol·L^-1ZnCl₂的乙腈溶液;电流密度为1.25A·dm^-2),0.08mol·L^-1PCP能高选择性地脱氯生成2,3,5,6-TCP,2,3,5,6-TCP的收率和电解电流效率分别可达88.7%和59.1%。     

介孔Cr(OH)3的制备及其对钒(Ⅴ)离子的吸附性能

以CrCl₃·6H₂O作为铬源,通过添加强碱制备出大比表面积（312.70 m²·g^-1）、高孔隙率（0.48 cm³·g^-1）的介孔Cr（OH）₃,并研究了其对溶液中钒（V）离子的吸附性能,考察了溶液pH、吸附剂用量、吸附温度、吸附时间等条件对吸附效果的影响。结果表明,当溶液pH在2.0~9.0、钒离子浓度为100~500 mg·L^-1时,采用该吸附剂均可实现溶液中钒离子的高效去除。在最优实验条件下,钒去除率接近100%,钒离子浓度可由500 mg·L^-1降至0.81 mg·L^-1。吸附热力学的研究结果表明,Cr（OH）₃对钒离子的吸附过程遵循Langmuir等温吸附;吸附过程符合拟二级反应动力学方程,反应级数为拟二级。     

单极脉冲电合成聚苯胺膜及其超级电容性能

采用单极脉冲电化学聚合方法在铂基体表面制备了具有三维网络结构的聚苯胺(PANI)纳米纤维膜。采用傅里叶变换红外(FT-IR)光谱和扫描电镜(SEM)分析比较了脉冲聚合和循环伏安聚合膜的组成和形貌,在0.5mol·L-1的硫酸溶液中通过恒电流充放电和电化学阻抗(EIS)等考察了聚合膜的电化学容量性能。研究表明,固定脉冲电压1.0V、苯胺单体浓度0.2mol·L-1时控制单极脉冲频率1.25s-1、占空比50%可获得高达699F·g-1比电容的纳米纤维结构PANI膜;聚合膜呈现均匀的三维有序网络状分布,其离子交换容量、循环稳定性及超级电容性能远高于循环伏安法聚合的PANI膜。     

Polypyrrole electropolymerized on aluminum alloy 1100 doped with oxalate and tungstate anions

Polypyrrole films doped with oxalic acid and tungstate were potentiostatically electropolymerized on aluminum alloy 1100. Two statistical factorial designs (fractional and complete) were used to study the influence of the synthesis variables on the film performance against corrosion. Corrosion protection of the polypyrrole films doped with oxalate and tungstate anions (PPy/OXA/W) on the aluminum alloy was evaluated by potentiometric and electrochemical impedance spectroscopy (EIS) measurements in a 0.05 mol L⁻¹ NaCl solution. The results obtained showed that the best performance against corrosion was detected with the PPy/OXA/W film synthesized at 1.0 V, 1.5 C in 0.2 mol L⁻¹ pyrrole, 0.1 mol L⁻¹ oxalic acid and 0.05 mol L⁻¹ sodium tungstate solutions provide a protective effect against corrosion.     

Ti/PbO_2电极上丙烯酰胺/丙烯酸共聚的电催化性能

采用热分解和电沉积的方法制备了Ti/PbO2电极,并在Ti/PbO2电极的电催化作用下,在引发剂硝酸铈铵存在的条件下,成功将丙烯酰胺(AM)和丙烯酸(AA)共同聚合为聚(丙烯酰胺-co-丙烯酸)[P(AM-co-AA)]。利用红外光谱(IR)和循环伏安曲线(CV)讨论了共聚产物及其过程的动力学规律;采用黏度法测定了共聚产物的分子量;考察了在不同单体配比的条件下电流密度、引发剂浓度对共聚产物分子量和共聚反应单体转化率的影响。结果表明:丙烯酰胺和丙烯酸可以在硝酸铈铵Ce(Ⅳ)和电化学催化共同作用下共聚;在单体配比n(AM)∶n(AA)=2.3∶1,电流密度I=0.125A·cm-2,引发剂用量ω[Ce(Ⅳ)]=0.8%的条件下制得相对分子质量为6.5×105的聚(丙烯酰胺-co-丙烯酸),转化率可达到70%。     

A comparative study of the physicochemical and electrochemical properties of Cr and Ni-W-P amorphous electrocoatings

A comparative study of the physicochemical and electrochemical properties of Cr and amorphous Ni-W-P electrocoatings is presented here. Amorphous Ni-W-P alloys were successfully produced by electrodeposition at 70 °C on copper substrate under galvanostatic control in the range of 50-400 mA cm⁻² and constant loads of 500 and 1600 C, using a solution containing 0.20 mol L⁻¹ Na₂WO₄.2H₂O; 0.02 mol L⁻¹ NiSO₄·6H₂O; 0.02 mol L⁻¹ NaPH₂O₂; 0.02 mol L⁻¹ H₃BO₃; 0.07 mol L⁻¹ (NH₄)₂SO₄; 0.20 mol L⁻¹ Na₃C₆H₅O₇·2H₂O; 0.0001 mol L⁻¹ CH₃(CH₂)₁₀·CH₂OSO₃Na. Cr electrocoatings were obtained from an industrial plating solution. The physicochemical characterization of the as-electrodeposited and as-annealed samples was carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray analysis (EDX) techniques. Corrosion tests were carried out at room temperature in 10⁻¹ mol L⁻¹ NaCl aqueous solutions, using potentiodynamic linear polarization (PLP). Among the various Ni-W-P electrocoatings studied here, the Ni₆₅W₂₀P₁₅ layer presented the best corrosion behavior and a slightly superior corrosion potential than the Cr electrocoating. Heat treatments gave rise to a cracked surface morphology in the Cr layers, while the surface morphology of the Ni₆₅W₂₀P₁₅ layers remained homogeneous and devoid of cracks. Heat treatments at 400 and 600 °C led to crystallization of the Ni-W-P layer, with precipitation of the Ni₃P, Ni and Ni-W phases and increasing hardness of the Ni-W-P layer as the heat treatment temperature rose. All the annealed Cr layers showed cracked surfaces and their hardness diminished as the annealing temperature increased. The presence of cracks impairs the mechanical and corrosion resistance properties of Cr layers. Ni₆₅W₂₀P₁₅ layer is a potential candidate to replace Cr in industrial applications, mainly at operational temperatures that exceed room temperature.     

Synthesis of Indium Nanowires by Galvanic Displacement and Their Optical Properties

Single crystalline indium nanowires were prepared on Zn substrate which had been treated in concentrated sulphuric acid by galvanic displacement in the 0.002 mol L⁻¹ In₂(SO₄)₃-0.002 mol L⁻¹ SeO₂-0.02 mol L⁻¹ SDS-0.01 mol L⁻¹ citric acid aqueous solution. The typical diameter of indium nanowires is 30 nm and most of the nanowires are over 30 μm in length. XRD, HRTEM, SAED and structural simulation clearly demonstrate that indium nanowires are single-crystalline with the tetragonal structure, the growth direction of the nanowires is along [100] facet. The UV-Vis absorption spectra showed that indium nanowires display typical transverse resonance of SPR properties. The surfactant (SDS) and the pretreatment of Zn substrate play an important role in the growth process. The mechanism of indium nanowires growth is the synergic effect of treated Zn substrate (hard template) and SDS (soft template).     

Amperometric flow injection analysis as a new approach for studying disperse systems

Fast and simple quantitative determination in dispersed systems (layered double hydroxides - LDHs - suspensions in aqueous solutions) was performed by a procedure that couples flow injection and amperometric detection (FI-AM). LDH dispersions are injected in a continuous flow (1 mL min⁻¹) of 0.05 mol L⁻¹ KNO₃ solution and [Cu(H₂O)₆]²⁺, used as a probe, is detected at a glassy carbon electrode housed in a flat electrochemical cell. The current intensity, recorded at the selected working potential (−0.25 V vs Ag/AgCl/NaCl (3 mol L⁻¹)), presents a linear relationship with [Cu(H₂O)₆]²⁺ concentration and the procedure offers high sensitivity (slope = 0.036 μA/(μmol L⁻¹)), a low detection limit (=0.7 μmol L⁻¹) and a wide quantification range (4-200 μmol L⁻¹).The method was applied to [Cu(H₂O)₆]²⁺ determination in two particular LDH-aqueous solution dispersed systems: (1) [Cu(H₂O)₆]²⁺ scavenging by etilendiammintetraacetic acid (EDTA) modified Zn-Al-LDHs, and (2) [Cu(H₂O)₆]²⁺ release from a copper doped Mg-Al-LDHs. The results obtained are comparable to those reported in previous works using different quantification techniques. FI-AM determination is applied without sample pretreatment (solid-supernatant separation) providing a high sampling rate (above 120 samples h⁻¹) that allows a better comprehension of the processes, particularly at the initial stages.     

电解合成对氨基酚反应催化剂

研究了硝基苯电解还原制备对氨基酚过程中的Bamberger重排反应。首先用循环伏安法考察了几种催化剂的催化活性,发现硅藻土、硫酸氧化锆、β沸石加入后硝基苯的还原峰电流有显著增大。还考察了羟基苯胺在不同条件下的转位效果。实验发现,酸性条件下,最佳反应条件为H+浓度为0.5～1mol·L-1、反应时间为15min,最佳无机酸为磷酸。温度为70℃时,硅藻土和硫酸氧化锆有较为显著的催化效果。     

基于ETS活性的有机物降解与硝化过程中微生物动力学

通过考察有机物生物降解和氨氮生物硝化过程中活性污泥电子传递体系（ETS）活性的变化规律,研究了ETS活性表征污泥生物活性的可行性,结合米门公式分析了有机物生物降解和硝化反应过程生物活性动力学。试验结果表明,活性污泥的ETS活性可以有效地揭示出有机物生物降解和氨氮生物硝化反应的进程,同时对系统受到的有机物和氨氮冲击负荷及硝化过程中碱度的变化有着灵敏的反映,这说明用ETS活性表征污泥的生物活性是可行的;有机物生物降解过程生物活性米氏常数K_s^T=368.9 mg·L^-1,U_m^T=90.9 mg TF·（g TSS·h）^-1,K_s^I=88.42 mg·L^-1,U_m^I=277.8 mg INTF·（g TSS·h）^-1;氨氮硝化过程生物活性米氏常数K_s^T=16.89 mg·L^-1,U_m^T=34.6 mg TF·（g TSS·h）^-1, K_s^I=6.0 mg·L^-1,U_m^I=196.08 mg INTF·（g TSS·h）^-1;生物活性动力学分析进一步验证了进行有机物生物降解的异养菌生长速率高于进行硝化反应的自养型硝化菌。     

离子液体BMIMBF4对全钒液流电池正极电解液的影响

为提高全钒液流电池的能量密度和正极电解液稳定性,采用循环伏安、交流阻抗等方法,研究了1-丁基-3-甲基咪唑四氟硼酸盐（BMIMBF₄）作为正极电解液添加剂对溶液稳定性和电化学反应活性的影响,并对其机理进行了初步探讨。实验结果表明,添加BMIMBF₄后,正极电解液中五价钒离子的稳定性显著提高,电解液的电化学反应活性也有所提升。当添加量为1%时,电池的单位体积电容量比有所增加,并且能量效率有所提升。     

Pt film electrodes prepared by the Pechini method for electrochemical decolourisation of Reactive Orange 16

Electrochemical decolourisation of Reactive Orange 16 was carried out in an electrochemical flow-cell, using as working electrodes a Pt thin film deposited on a Ti substrate (Pt/Ti) prepared by the Pechini method and a pure platinum (Pt) foil. Using the Pt/Ti electrodes better results for dye decolourisation were obtained under milder conditions than those used for pure Pt. For the Pt electrode, colour removal of 93 % (λ = 493 nm) was obtained after 60 min, at 2.2 V vs. RHE, using 0.017 mol L⁻¹ NaCl + 0.5 mol L⁻¹ H₂SO₄ solution. For the Pt/Ti electrode there was better colour removal, 98%, than for the Pt electrode. Moreover, we used 0.017 mol L⁻¹ NaCl solution and the applied potential was 1.8 V. Under this condition after 15 min of electrolysis, more than 80% of colour was removed. The rate reaction constant, assuming a first order reaction, was 0.024 min⁻¹ and 0.069 min⁻¹, for Pt and Pt/Ti electrodes, respectively.