Sb和S修饰Pt电极上1,3 -丁二醇氧化的原位红外反射光谱研究

运用电化学原位ＦＴＩＲ反射光谱研究了１,３－丁二醇在以Ｓｂ和Ｓ修饰的Ｐｔ电极上的氧化过程。结果表明Ｓｂ和Ｓ修饰都能抑制１,３丁醇的解离吸附。红外数据指出Ｓｂ的存在使１,３丁二醇氧化产物同时含有羰基物种和ＣＯ２,而Ｓ修饰的Ｐｔ电极上以羧酸物种为主。     

拉曼光谱研究Pt电极上欠电位沉积Sn对甲醇氧化的影响

本文采用拉曼光谱研究Ｐｔ电极上欠电位沉积（亚）单原子层的Ｓｎ对甲醇氧化的影响,初步的结果表明,欠电位沉积Ｓｎ促进了Ｐｔ上甲醇的电催化氧化,与纯Ｐｔ电极体系相比较,作为表面毒性中间物的ＣＯ在较负电位下即可被氧化。本文对其可能的机理进行了初步的讨论     

ω-巯基己酸自组装修饰金电极及其对叶绿素的催化氧化还原作用

用自组装技术以ω－巯基己酸（６－ＭＨＡ）对金电极进行修饰。通过表面增强拉曼散射（ＳＥＲＳ）光谱和电化学方法研究了６－ＭＨＡ自组装单分子膜（ＳＡＭ）在金电极表面的形成及由此引起的电极双电层电容的变化,并研究了该自组装单分子膜的结构模型及修饰电极对叶绿素的催化性能。结果表明,６－ＭＨＡ在金电极表面能够形成一层自组装膜,并对叶绿素的氧化还原过程具有明显的催化作用。     

超氧化物歧化酶在L—半胱氨酸修饰金电极上电化学行为的现场拉曼 …

在以电化学方法确认Ｌ－半胱氨酸对铜－锌超氧化物歧化酶（ｃｏｐｐｅｒ,ｚｉｎｃ ｓｕｐｅｒｏｘｉｄｅ ｄｉｓ－ｍｕｔａｓｅ,ＳＯＤ）在金丝电极上的电子迁移过程起促进作用的基础上,本文论述了将拉曼光谱电化学方法应用于猪红细胞ＳＯＤ在经Ｌ－半胱氨酸修饰的金丝电极上的金电极上的电化学行为的现场拉曼光谱研究。研究结果从分子水平上提供了有关Ｌ－半胱氨酸修饰在金电极上的电化学过程中,以及ＳＯＤ在Ｌ－半胱氨酸修饰     

纳米薄膜合金电极上二氧化碳电催化还原的红外光谱研究

运用电化学循环伏安和原位ＦＴＩＲ反射光谱，研究ＣＯ２的电催化还原过程。结果表明，纳米薄膜合金材料Ｓｂ－Ｐｂ－Ｐｔ／ＧＣ对ＣＯ２还原具有较高的活性。还原产物以小分子羧酸和伯醇为主。     

表面合金电催化剂上甲酸氧化的原位FTIR反射光谱研究

运用原位红外反射光谱(FTIRS)和电化学循环伏安法(CV)研究了甲酸在三种不同电极上的电催化特性。结果表明甲酸在碳载铂电极(Pt/GC)上的电催化氧化机理与本体铂电极(Pt)相类似,即可以通过活性中间体或毒性中间体氧化至CO_2。Pt/GC对甲酸的氧化比Pt具有更高的电催化活性。Pt/GC表面以Sb吸附原子修饰的电极(Sb-Pt/GC)上,甲酸氧化的起始电位(E;)提前至-0.10V,氧化电流峰电位(Ep)提前至0.34V,氧化峰电流(jp)值增加了7.28倍,半峰宽(FWHM)为0.30V。同样,Surface al-loy/GC电极上,E_I为-0.12V,E_p为0.32V和j_p为7.25mA·cm~(-2),相对Pt/GC分别负移了0.22,0.02V和增大了8.15倍,半峰宽(FWHM)为0.5V。表明Sb-Pt/GC和Surface alloy/GC电极不仅能够有效地抑制毒性中间体CO的生成,而且还可以显著地提高其对活性中间体的氧化的电催化活性。     

甲酸在铂钌电极上电催化氧化的原位SERS研究

采用循环伏安法和电化学原位表面增强拉曼光谱(in-situ SERS)技术研究了甲酸在铂钌电极上解离吸附与氧化行为。发现甲酸在铂钌电极上也能自发解离吸附。铂钌电极上CO的氧化峰电位与粗糙铂电极相比负移了180mV,把CO氧化完毕的电极电位亦负移了300 mV,从分子水平证实铂钌电极对甲酸电催化氧化的活性比纯铂电极更高。该研究结果表明,SERS技术可望拓展为研究电催化体系的有效工具。     

3,3‘,5,5’—四甲基联苯胺——β—环糊精包合物的紫外—可见光谱和电？…

本文采用紫外－可见光谱和电化学的方法研究了３,３’,５,５’－四甲基联苯胺（ＴＭＢ）和β－环糊精形成超分子包合物后的氧化还原性质,研究结果表明在形成包合物后ＴＭＢ的氧化还原特性更好,尤其是在有酶参与时更易被氧化。在包合物内的氧化产物组分更单纯,修饰在电极表面也表现出更好的氧化还原活性。     

清洁及氧修饰Cu（100）表面上水煤气变换反应的能量学

分别以清洁及氧修饰Ｃｕ（１００）表面作为金属态铜和部分氧化态铜的表面模拟，用键级守恒Ｍｏｒｓｅ势法研究了两种表面上水煤气变换（ＷＧＳ）反应的能量学。计算结果表明：清洁Ｃｕ（１００）表面上，ＷＧＳ反应有可能同时按表面氧化还原和甲酸根两种机理进行；表面氧化还原机理中，ＣＯｓ主要由ＯＨｓ（而不是Ｏｓ）氧化为ＣＯ２ｓ。与清洁铜表面相比，Ｃｕ（１００）ｐ（２×２）Ｏ表面上ＷＧＳ反应中活化能最大的基元步骤Ｈ２     

[OsⅣ（N）（NH3）4]（CF3SO3）3电化学还原过程的原位FTIR光 …

运用原位ＦＴＩＲＳ,ＵＶ／Ｖｉｓ和电化学方法研究了乙腈溶液中「ＯｓⅣ（Ｎ）（ＮＨ３）４」（ＣＦ３ＳＯ３）３在ＧＣ和Ｐｔ电极上的还原过程。结果首次在Ｐｔ电极上检测到桥氮物种υ（Ｎ≡Ｎ）的红外谱峰,位于２０１９和１９７０ｃｍ＾－１附近,分别指认为「Ⅲ,Ⅱ」和「Ⅱ,Ⅱ」混合价桥氮俄络合物。为进一步探讨桥氮偶联过程提供了新的谱学数据。     

Structure and reactivity of bimetallic electrochemical interfaces: infrared spectroscopic studies of carbon monoxide adsorption and formic acid electrooxidation on antimony-modified Pt(100) and Pt(111)

The influence of predosed antimony on the adlayer structures of carbon monoxide and on the electro-oxidation kinetics of formic acid on Pt(100) and Pt(111) in 0.1M HClO₄ is examined by means of in-situ infrared spectroscopy in conjunction with cyclic voltammetry. Preadsorbed antimony inhibits the adsorption of CO on these surfaces, the attenuation in CO coverage being accompanied by a selective removal of the two-fold bridging geometry as deduced from the relative ν_CO band intensities. At saturation antimony coverages, the CO binding is exclusively terminal on Pt(100) and Pt(111). These findings are consistent with the adsorption of antimony at multi-fold sites, yielding microscopically intermixed adlayers with CO. The electro-oxidation rates of formic acid are enhanced substantially by preadsorbed antimony on Pt(100) and Pt(111). The real-time infrared spectra in the C-O stretching region and the CO coverages thereby deduced in the presence of predosed antimony under reactive voltammetric conditions suggest that the metal adatoms are actively involved in the dissociation of formic acid. The origins of the enhanced electrocatalytic activity of the bimetallic Sb/Pt surfaces are discussed in terms of geometric and chemical effects.     

Surface (electro-)chemistry on Pt(1 1 1) modified by a Pseudomorphic Pd monolayer

The formic acid and methanol oxidation reaction are studied on Pt(1 1 1) modified by a pseudomorphic Pd monolayer (denoted hereafter as the Pt(1 1 1)-Pd_1 ML system) in 0.1 M HClO₄ solution. The results are compared to the bare Pt(1 1 1) surface. The nature of adsorbed intermediates (CO_ad) and the electrocatalytic properties (the onset of CO₂ formation) were studied by FTIR spectroscopy. The results show that Pd has a unique catalytic activity for HCOOH oxidation, with Pd surface atoms being about four times more active than Pt surface atoms at 0.4 V. FTIR spectra reveal that on Pt atoms adsorbed CO is produced from dehydration of HCOOH, whereas no CO adsorbed on Pd can be detected although a high production rate of CO₂ is observed at low potentials. This indicates that the reaction can proceed on Pd at low potentials without the typical “poison” formation. In contrast to its high activity for formic acid oxidation, the Pd film is completely inactive for methanol oxidation. The FTIR spectra show that neither adsorbed CO is formed on the Pd sites nor significant amounts of CO₂ are produced during the electrooxidation of methanol.     

Functional multi-walled carbon nanotube/polyaniline composite films as supports of platinum for formic acid electrooxidation

Embedding of carbon nanotubes in conducting polymeric matrices for various nanocomposites material is now a popular area. In this article, a concise chemical method has been described for the preparation of homogeneous nanocomposite of multi-walled carbon nanotube (MWNT)/polyaniline (PANI) by electrochemical codeposition. For this we functionalized the MWNTs via the diazotization reaction. This helped to disperse the nanotubes in aniline. The composite films were dispersed Pt by electrodeposition technique. The presence of MWNTs and platinum in the composite films was confirmed by XRD analysis and transmission electron microscopy (TEM). Four-point probe investigations revealed that the MWNT/PANI composite films exhibited a good conductivity. Cyclic voltammograms (CV) showed that Pt-modified MWNT/PANI composite films perform higher electrocatalytic activity and better long-term stability than Pt-modified pure PANI film toward formic acid oxidation. The results imply that the MWNT/PANI composite films as a promising support material improves the electrocatalytic activity for formic acid oxidation greatly.     

重新审视桥式吸附甲酸根在铂电极上电催化氧化甲酸过程中的作用 (cited: 2)

基于以前报道的电化学原位ATR-FTIRS数据(Langmuir 22,10399 (2006)和Angewa. Chem. Int. Ed., 50,1159 (2011)),详细讨论了甲酸在铂电极上电催化氧化机理及动力学过程．提出了直接反应路径的动力学模型,即甲酸吸附(同时C-H键活化)作为此反应的决速步骤,此反应路径贡献甲酸氧化反应的大部分电流．该动力学模型可以很好地拟合在无CO毒化影响和浓度在0.1 mol/L以下的红外光谱结果．这种机理预测了甲酸氧化直接途径可能只需要一个Pt原子作为反应位点,甲酸根阻碍活性位点,并非为反应中间物．另外还详细检验了之前其他小组曾提出的甲酸根途径(一级或二级反应)为甲酸氧化直接途径,并指出了引起分歧的原因．     

Efficient electrocatalysis of formic acid oxidation onto Pd-Cu/poly (2-methoxyaniline)-SDS nanocomposite film

In this work, porous poly (2-methoxyaniline) film prepared in the presence of sodium dodecyl sulfate (P2MA-SDS) is used as a potent support for dispersion of bimetallic palladium-copper nanoparticles (Pd-Cu NPs) towards the electrooxidation of formic acid (HCOOH) in sulfuric acid solution. The Pd-Cu NPs are prepared through galvanic replacement reaction between Pd^II ions and Cu particles. The SEM, EDS, and electrochemical methods were used to characterize the prepared Pd-Cu NPs. The obtained results show that the Pd-Cu exhibited significantly high current density of HCOOH oxidation compared to other catalysts and utilization of Cu NPs enhances the electrocatalytic activity towards electrooxidation. The enhanced performance is related to the synergetic effect between Pd-Cu NPs and P2MA-SDS film. The effects of galvanic replacement time, potential sweep rates, and concentration of HCOOH on the catalytic activity of the electrocatalyst as well as long-term stability are investigated by the various electrochemical techniques.     

电化学红外光谱研究铂电极上甲酸分解成CO的反应中桥式吸附甲酸根的作用

采用电化学原位红外光谱技术研究了多晶Pt电极上甲酸的分解反应. 研究发现,在恒电位下(0.4 V vs. RHE)从不含甲酸的支持电解质溶液切换到含甲酸的溶液时,CO_ad的生成速率在切换的最初也就是甲酸根的覆盖度为零最大,切换后的1 s内甲酸根的覆盖度达到平衡,而COad的生成速率逐步降低. E由0.75 V变至0.35 V的电位阶跃实验显示：电位阶跃后的瞬间,甲酸根的红外光谱强度迅速降低,而CO_ad的生成强度随时间缓慢增加. 实验表明甲酸根不是甲酸脱水生成CO的反应活性中间体.     

Successive electrodeposition of polydopamine and PtPd metal on a graphene oxide support for use as anode fuel cell catalysts

Successive electropolymerization of dopamine and electrodeposition of Pd and/or Pt on a graphene oxide (GO) support were used to prepare anode catalysts for low-temperature fuel cells. Transmission electron microscopy images were used to investigate the morphologies and distribution of the prepared catalysts, which showed the metal formed as nanoparticles on the catalysts. The GO surface was favorable for the modification with electropolymerized polydopamine (PDA) and the electrodeposition of metal catalyst nanoparticles using a simple preparation process. The PDA-loaded GO composite was used as a matrix for the dispersion of Pt and Pd nanoparticles. GO could be simultaneously modified by PDA and reduced without using reducing agents. The electrocatalytic performance of the catalysts for the oxidation of selected small molecule fuels (e.g., methanol, ethanol and formic acid) was examined. An outstanding catalytic activity and stability was found for the prepared Pt/Pd/PDA/GO composite, which was attributed to the high active surface area.