还原态聚苯胺的光电化学研究

本文研究了还原态聚苯胺修饰电极的光电化学。通过不同基底电极、饱和气氛、温度、扰动方法（光照电极、电极旋转、气体鼓泡搅拌溶液、顺电极表面向电解池滴加电解液等）对还原态聚苯胺电流响应的影响及光谱分析，首次发现还原态聚苯胺的光电流响应并不是由于其吸收可见或近红外光激发而引起的，光的作作是通过扰动电极表面，促进电解质溶液中溶解的氧气对聚苯胺的氧化，仪器为了维持恒电位将氧化了的聚苯肢再还原而产生光电流响应。     

可溶导电聚苯胺的合成及其性能研究

以十二烷基苯磺酸（ＤＢＳＡ）为乳化剂和掺杂剂，采用水一油二相乳液聚合物方法对苯胺进行合成，制备出高溶解性和高电导率的ＰＡｎ，通过ｘ－射线，电镜分析和热重分析对产物的结构和性能进行了研究。结果表明，该法合成的导电性ＰＡｎ具有较高的特性粘度，溶解性，耐热性及结晶度，与非极性溶剂－表面活性剂－水三相体系聚合产物结果相似，透射电镜显示水乳液聚合产物呈较规则的纤维状取向排列。     

一维聚苯胺纳米材料的制备方法研究进展

一维聚苯胺纳米材料具有电导率高、环境稳定性好、分散性好、比表面积大、扩散路径短等独特性能以及易于大量生产和成本相对低廉等优点,在传感器与传动器、防腐涂料、电磁屏蔽等领域应用潜力大,成为目前研究最为广泛的导电聚合物纳米材料之一,其制备方法也日益成为研究的热点。综述了近年来一维聚苯胺纳米材料制备方法的最新研究进展,介绍了模板法、非模板法和电纺法等制备方法,并对各种不同制备方法的优缺点进行了比较分析。     

聚苯胺纳米颗粒的制备及其电化学性能

以乙醇和水为混合溶剂,采用氧化法制备了纳米尺度的聚苯胺颗粒。采用扫描电镜、红外光谱、循环伏安、恒流充放电及交流阻抗等测试手段对其结构和电化学性能进行了测试。研究了混合溶剂的比例对产物电化学性能的影响。结果表明：聚苯胺颗粒大小为50～100 nm;以制备的聚苯胺纳米颗粒为活性物质,在1 mol/L的H2SO4电解液中,当...     

化学合成环取代聚苯胺的电化学行为

聚邻甲苯胺（ＰＯＴ）、聚２,５ 二甲氧苯胺（ＰＤＭＡｎ）和聚间氯代苯胺（ＰＣｌＡｎ）由化学法合成而得,用它们的二甲基甲酰胺溶液在铂上成膜以制得聚合物修饰电极．循环伏安实验表明：在１ｍｏｌ／ＬＨ２ＳＯ４中,ＰＯＴ的氧化还原分两步进行,呈现两对氧化还原峰,ＰＤＭＡｎ只在较负的电位区呈现两对氧化还原峰,而ＰＣｌＡｎ不呈氧化还原活性．不同电位下的交流阻抗特征与循环伏安图相对应．三种聚合物膜电极在０．５ｍｏｌ／ＬＫ３［Ｆｅ（ＣＮ）６］溶液中的伏安图也证明铁氰离子的还原速度依ＰＯＴ＞ＰＤＭＡｎ＞ＰＣｌＡｎ的顺序而下降．环取代基的影响用电子效应和几何效应进行解释．可溶性聚苯胺便于制作大面积器件,环取代基对调节聚苯胺的电化学性能具有重要作用,值得进一步研究．     

聚苯胺的电化学现场ESR-电导同步测量

本论文工作通过设计新型的电解池 ,首次实现了导电聚合物的电化学现场ESR_电导同步测量 .从获得的聚苯胺ESR信号及膜电阻随电极电势变化的精细图象看出 ,极化子晶格的形成与消亡决定了聚苯胺的导电行为 .从不同电势下聚苯胺的ESR饱和行为也得到Curie自旋与Pauli自旋相互转化的新证据 .     

导电聚苯胺与磁性γ-Fe2O3纳米复合物的电磁性能

将无机磁性纳米粒子与导电高分子进行化学复合方面的研究已引起了人们的关注[1,2]. 由于该复合材料同时具有有机和无机材料的优异性能, 因而展示了巨大的应用潜力, 特别是在光、电和磁等领域的潜在应用前景更引起了各国研究者的高度重视[3～7].     

导电聚苯胺呋喃的结构表征

碘掺杂聚苯胺呋喃是一类非共轭导电聚合物。用紫外吸收光谱、傅里叶变换红外吸收光谱、电子顺磁共振波谱、光电子能谱等对该聚合物的结构性质及导电机制进行了研究。     

聚苯胺的质子酸掺杂机制的研究

木文用FT-IR、ESR、XPS等研究了聚苯胺的质子酸掺杂机制。结果表明聚苯胺掺杂时的质子化反应优先发生在分子链中的醌亚胺结构单元的氮原子上,并产生了分子内氧化还原反应而形成阳离子自由基。质子所带的电荷由于共轭作用能较好地离域到邻近苯环及对位氮原子上。     

聚苯胺自支撑导电膜的电化学合成及性能

采用电化学方法，以高氯酸为掺杂剂，合成了具有较好导电性能和机械性能的聚苯胺自支撑膜。探讨了电化学聚合反应条件对其性能的影响，并借助ＳＥＭ、ＩＲ、ＥＳＲ等手段表征了所得聚合物。     

Nonaqueous synthesis of uniform polyaniline nanospheres Via cellulose acetate template

In acetone solution, uniform polyaniline (PANI) nanospheres have been successfully synthesized by using cellulose acetate (CA) as a single template, which provides the first example of uniform PANI nanospheres synthesized in nonaqueous system. Our result exhibits that the CA micelle in nonaqueous medium plays a unique role in controlling size and uniformity of PANI nanospheres. A detail formation mechanism for the uniform PANI nanospheres has been proposed. In addition, the gas sensitivity and time response of the PANI nanospheres to NH₃ gas have been investigated, which shows superior gas sensing performance even at 1 ppm of NH₃ gas. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

SnO_(2)/ITO光电化学电极制备及性能研究EI北大核心CSCD

采用商品化氧化铟锡(ITO)导电玻璃、纳米SnO_(2)水胶体分散液,通过旋涂法制备了高性能SnO_(2)/ITO电极,考察了SnO_(2)旋涂浓度、旋涂量、Triton X-100浓度、煅烧温度对SnO_(2)/ITO电极性能的影响,并优化了缓冲体系、pH、浓度及偏压条件。结果表明,当SnO_(2)水胶体分散液浓度15%、Triton X-100浓度0.01%、煅烧温度450℃时,制备的SnO_(2)/ITO电极具有较高的热稳定性和光电化学性能;草酸-草酸钠缓冲体系有利于光电流的产生,当草酸浓度为30 mmol/L(pH 6.0)、偏压为0.5 V时,可以产生较高的稳态光电流信号,以Ru(bpy)_(2)(dppz)^(2+)为光电化学信号探针,检测限为10 nmol/L。考察了ITO电极的性能差异性,同一批次及不同批次之间的光电流信号一致性相对标准偏差(RSD)在3.9%~5.6%之间。     

The effect of the polyaniline morphology on the performance of polyaniline supercapacitors

The polyaniline (PANI) prepared by the pulse galvanostatic method (PGM) or the galvanostatic method on a stainless steel substrate from an aqueous solution of 0.5 mol/l H₂SO₄ with 0.2 mol/l aniline has been studied as an electroactive material in supercapacitors. The electrochemical performance of the PANI supercapacitor is characterized by cyclic voltammetry, a galvanostatic charge–discharge test and electrochemical impedance spectroscopy in NaClO₄ and HClO₄ mixed electrolyte. The results show that PANI films with different morphology and hence different capacitance are synthesized by controlling the synthesis methods and conditions. Owing to the double-layer capacitance and pseudocapacitance increase with increasing real surface area of PANI, the capacitive performances of PANI were enhanced with increasing real surface area of PANI. The highest capacitance is obtained for the PANI film with nanofibrous morphology. From charge–discharge studies of a nanofibrous PANI capacitor, a specific capacitance of 609 F/g and a specific energy density of 26.8 Wh/kg have been obtained at a discharge current density of 1.5 mA/cm². The PANI capacitor also shows little degradation of capacitance after 1,000 cycles. The effects of discharge current density and deposited charge of PANI on capacitance are investigated. The results indicate that the nanofibrous PANI prepared by the PGM is promising for supercapacitors.     

Preparation and photoelectrochemical characterization of nano-particulate TiO2 and polyaniline composite films on Au

TiO₂ and polyaniline(PANI) composite film was obtained by electrochemical methods^[1] and investigated for solar energy conversion application. A strong rectifying effect was found in the cyclic voltammogram of the film in dark when the scan speed was slow enough (5 mV/s) and a quasi-reversible voltammogram of the film was observed when the scan speed was fast (100 mV/s). The results of both the cyclic voltammograms and the SEM images of the composite film show that the PANI film is almost completely covered with nano-particulate TiO₂. Two anodic photocurrent bands and a cathodic band was observed in the spectra of the photocurrent of the TiO₂/PANI/PATP(p-aminothiophenol)/Au film in 0.05 mol/L Fe(CN)₆^3-/Fe(CN)₆^4- solution. The band at 300~400 nm (3.1~4.1 eV) can be ascribed to the photocurrent band of TiO₂ particles and the bands at 450~730 nm (1.7~2.8 eV) can be ascribed to those of the PANI. The partially-oxidized PANI has internal photoemission function and the insulating matrix of PANI is verified to be reduced PANI with a 3.33 eV bandgap energy. The flat-band potentials of partially-oxidized PANI and TiO₂/PANI composite film in 1.0 mol/LHClO₄ solution are determined as 0.87 V and 0.09(SHE) from Mott-Schottky plots, respectively.     

Hydroxyl-functionalized polyaniline nanospheres: tracing molecular interactions at the nanosurface via vitamin C sensing

Here, we report a synthesis of novel polyaniline nanospheres bearing mono- and bishydroxyl functional groups to trace the molecular interactions at the nanosurfaces through vitamin C sensing. Two new aniline monomers were synthesized via a tailor-made approach and polymerized to produce soluble and uniform polyaniline nanospheres. The structures of the monomers and polymers were characterized by NMR, FT-IR, and MS techniques, and the morphology of the nanomaterials was analyzed by SEM and TEM. The mechanistic aspects of the nanomaterial formations were analyzed by FT-IR and dynamic light scattering techniques. These studies revealed that the hydroxyl-functionalized monomers have strong hydrogen bonding at the monomer level and form spherical aggregates in water, which are templates for the polyaniline nanospheres 600 +/- 100 nm in size. A controlled synthesis was also carried out using aniline hydrochloride as an unsubstituted counterpart, which yields polyaniline nanofibers. WXRD analysis confirmed the presence of a sharp peak at lower angle at 2theta = 7.3 degrees ( d-spacing of 13.4 A) in hydroxyl-substituted nanospheres with respect to enhancement of solid-state ordered crystalline domains, whereas unsubstituted nanofibers were found to be highly amorphous. Vitamin C was employed as an analyte to trace the molecular interaction at the nanosphere surface and study the influence of nanosurface functionalization on the sensing ability of biomolecules. The bishydroxyl-functionalized polyaniline nanospheres were found to show efficient molecular interactions toward vitamin C, whereas nanospheres with a monohydroxyl group or unsubstituted nanofibers failed as sensing materials. In a nut shell, in the present investigation, for the first time, we have proved the importance of surface functionalization of polyaniline nanomaterial, exclusively nanospheres, using hydroxyl groups for studying the molecular interactions at the nanosurfaces with biomolecules such as vitamin C.     

Surface modification of semiconductor photoelectrodes for better photoelectrochemical performance

The present paper describes the modification and solar hydrogen production studies employing a new semiconductor-septum (SC-SEP) photoelectrode ns-TiO₂/In₂O₃ based photoelectrochemical solar cell. The current-voltage characteristics of the above SC-SEP cell revealed that an enhancement in short-circuit current (I_SC) up to three times (5 ～ 14.6 mA cm^?2). The optimum hydrogen production rate was found to be 11.8 lh^?1 m^?2 for 5M H₂SO₄ and with a further increase in H₂SO₄ concentration, the hydrogen production rate was found to be invariant. In yet another part of our study instead of using new SC-SEP solar cell design, we used another new oxide material form such as ns-TiO₂/WO₃. The ns-TiO₂/WO₃ exhibited a high photocurrent and photo-voltage of 15.6 mA cm^?2, 960 mV, respectively. The ns-TiO₂/WO₃ electrode exhibited a higher hydrogen gas evolution rate of 13.8 lh^?1 m^?2. Evidences and arguments are put forward to show that, whereas for the bare ns-TiO₂ electrode, the improvement in the performance of this photo-electrode compared with its original form was due to the higher quantum yield. In the case of ns-TiO₂/In₂O₃ and ns-TiO₂/WO₃ photo-electrodes, the improvement is due to the improved spectral response resulting from decrease of energy band gap.     

Capacitive storage performance of nanorod assembly of polyaniline

Journal of Solid State Electrochemistry - Herein, we report a good capacitive storage performance of nanorod assembly of polyaniline (PANI). PANI was synthesized by a facile method using...     

Influence of surfactants on electrochemical growth of CdSe nanostructures and their photoelectrochemical performance

Cadmium selenide (CdSe) thin films were grown by electrochemical technique on fluorine-doped tin oxide (FTO)-coated conducting glass substrates in the presence of organic surfactants. The influence of organic surfactants like polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) on different physico-chemical properties and its subsequent impact on photoelectrochemical (PEC) performance of CdSe thin films have been investigated. It has observed that the organic surfactants play an important role in modifying the surface morphology of CdSe thin films. The compact grain like morphology of pure CdSe is tuned to interconnected nanofibrous network on addition of PEG and to sprouting nanorods like morphology on addition of PVP. Among these nanostructures, CdSe sprouting nanorods exhibits improved power conversion efficiency of 0.55% as compared to nanofibrous (0.24%) and granular CdSe (0.16%) nanostructures. It reveals the fourfold enhancement in the PEC performance on PVP-mediated growth which can be attributed to conversion of compact dense nanostructure to porous and relatively high surface area nanostructure. This work exemplifies the ability of organic surfactant to modulate the surface morphology of the electrodeposits and pinpoints the organic surfactant that gives rise to the suitable morphology for PEC solar cell application.

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Graphical abstract TOC: The morphology of CdSe nanostructure has successfully tuned with use of surfactants to enhance the photoelectrochemical solar cell performance.

     

CdS纳米微球的制备及其荧光性质的研究

本文以溶剂热法制得了CdS纳米微球体,并且采用XRD、SEM,PL等测试手段对产物进行了表征。实验结果表明:PVP、TU、Cd2+量及反应时间对产物的颗粒大小和荧光有显著的影响。在140℃下,以硫脲为硫源,乙二醇为溶剂制得的CdS纳米微球体具有良好的形貌,外形规则,直径大约200-300nm。荧光光谱分析表明PVP、Cd2+量的增大及反应时间的延长使CdS微球体的峰值发生红移,TU量的增大使峰值先红移后蓝移。通过改变反应条件,实现了对CdS纳米微球的荧光性质的调控。     

CdS nanocrystallites sensitized ZnO nanorods with plasmon enhanced photoelectrochemical performance

A novel architecture of CdS/ZnO nanorods with plasmonic silver (Ag) nanoparticles deposited at the interface of ZnO nanorods and CdS nanocrystallites, was designed as a photoanode for solar hydrogen generation, with photocurrent density achieving 4.7 mA/cm² at 1.6 V (vs. RHE), which is 8 and 1.7 times as high as those of pure ZnO and CdS/ZnO nanorod films, respectively. Additionally, with optical absorption onset extended to ～660 nm, CdS/Ag/ZnO nanorod film exhibits significantly increased incident photo-to-current efficiency (IPCE) in the whole optical absorption region, reaching 23.1% and 9.8% at 400 nm and 500 nm, respectively. The PEC enhancement can be attributed to the one-dimensional ZnO nanorod structure maintained for superior charge transfer, and the extended visible-light absorption of CdS nanocrystallites. Moreover, the incorporated plasmonic Ag nanoparticles could further promote the interfacial charge carrier transfer process and enhance the optical absorption ability, due to its excellent plasmon resonance effect.