Ag／γ－Al_2O_3催化剂的TPR和TPD研究

本文运用ＴＰＤ－ＭＳ、ＴＰＲ等方法研究了Ａｇ／γ－Ａｌ_２Ｏ_３催化剂的氧脱附和还原性能。结果表明，Ａｇ／γ－Ａｌ_２Ｏ_３催化剂表面银物相由Ａｇ０和Ａｇ＋（Ａｇ２Ｏ）组成，其中Ａｇ＋所占比例随负载量增加而减少。Ａｇ／γ－Ａｌ_２Ｏ_３催化剂有三个脱氧峰，并且随着Ａｇ负载量的增加，脱氧峰从高温向低温依次出现。低温脱氧峰（３７０℃）归属为结晶态Ａｇ２Ｏ的分解，高温脱氧峰（６５０和８００℃）为分散在γ－Ａｌ_２Ｏ_３表面并且与Ａｌ_２Ｏ_３发生相互作用的Ａｇ_２Ｏ的分解。ＴＰＲ有三个还原峰；高温峰（２３０℃）为结晶态Ａｇ_２Ｏ的还原，低温峰（１００和１２０℃）为分散在γ－Ａｌ_２Ｏ_３表面的Ａｇ_２Ｏ的还原。     

Mn－Ag／γ－Al_2O_3催化剂中氧的性能

本文运用ＴＰＲ、ＴＰＤ－ＭＳ、ＸＲＤ等技术研究了Ｍｎ－Ａｇ／γ－Ａｌ_２Ｏ_３催化剂的还原性能和再氧化能力．结果表明，Ｍｎ－Ａｇ／γ－Ａｌ_２Ｏ_３中银物相由Ａｇ￣０和Ａｇ_２Ｏ组成，锰物相由β－ＭｎＯ_２和Ｍｎ２Ｏ_３组成．Ｍｎ／γ－Ａｌ_２Ｏ_３催化剂的ＴＰＲ有二个还原峰，分别是ＭｎＯ_２和Ｍｎ_２Ｏ_３的还原．Ａｇ促使ＭｎＯ_２和Ｍｎ_２Ｏ_３的还原明显向低温方向移动，而且ＭｎＯ_２和Ｍｎ_２Ｏ_３的还原峰融合成一个还原峰．Ｍｎ－Ａｇ／γ－Ａｌ_２Ｏ_３的ＴＰＤ有三个脱氧峰，随着Ａｇ含量增加，峰Ⅰ向高温方向移动，Ｍｎ￣（４＋）２ｐ３／２的电子结合能增加，并且催化剂的再氧化能力增强．催化剂ＣＯ的氧化活性与催化剂的再氧化能力有很好的对应关系．     

Mn—Ag／r—Al2O3催化剂中氧的性能

本文运用ＴＰＲ、ＴＰＤ－ＭＳ、ＸＲＤ等技术研究了Ｍｎ－Ａｇ／ｒ－Ａｌ２Ｏ３催化剂的还原性能和再氧化能力。结果表明，Ｍｎ－Ａｇ／ｒ－Ａｌ２Ｏ３中银物相由Ａｇ＾０和Ａｇ２Ｏ组成，锰物相由β－ＭｎＯ２和Ｍｎ２Ｏ３组成。Ｍｎ／ｒ－Ａｌ２Ｏ３催化剂的ＴＰＲ有二个还原峰，分别是ＭｎＯ２和Ｍｎ２Ｏ３的还原。Ａｇ促使ＭｎＯ２和Ｍｎ２Ｏ３的朱明显向低温方向移动，而且ＭｎＯ２和Ｍｎ２Ｏ３的还原峰融合成一个还原峰。Ｍｎ     

Ag／γ—Al2O3催化剂的TPR和TPD研究

本文运用ＴＰＤ－ＭＳ，ＴＰＲ等方法研究了Ａｇ／γ－Ａｌ２Ｏ３催化剂的氧脱附和还原性能，结果表明，Ａｇ／γ－Ａｌ２Ｏ３催化剂表面银物相由Ａｇ＾０和Ａｈ＾＋（Ａｇ２Ｏ）组成，其中，Ａｇ＾＋所占比例随负载量增加而减少。     

CO2在Ag—Ba—Ca—K／α—Al2O3上的吸附及其在乙烯环氧化反应中的抑制作用

应用ＦＴＩＲ和脉冲反应技术研究了ＣＯ２和Ｏ２在Ａｇ－Ｂａ－Ｃａ－Ｋ／α－Ａｌ２Ｏ３上的吸附及ＣＯ２对Ｃ２Ｈ４环氧化，完全氧化及环氧乙烷（ＥＯ）深度氧化反应的影响。研究结果表明，ＣＯ２和表面吸附氧在负载银催化剂表面存在竞争吸附，ＣＯ２对表面吸附氧有置换作用，该作用降低了银催化剂表面吸附氧的浓度，并且所形成的碳酸根物种改善了乙烯环氧化反应活性氧种的表面分布，对Ｃ２Ｈ４的环氧化反应有一定的抑制作用，但是     

CO_2在Ag－Ba－Ca－K／α－Al_2O_3上的吸附及其在乙烯环氧化反应

应用ＦＴＩＲ和脉冲反应技术研究了ＣＯ_２和Ｏ_２在Ａｇ－Ｂａ－Ｃａ－Ｋ／α－Ａｌ２Ｏ３上的吸附及ＣＯ２对Ｃ２Ｈ４环氧化、完全氧化及环氧乙烷（ＥＯ）深度氧化反应的影响．研究结果表明，ＣＯ２和表面吸附氧在负载银催化剂表面存在竞争吸附，ＣＯ２对表面吸附氧有置换作用，该作用降低了银催化剂表面吸附氧的浓度，并且所形成的碳酸根物种改善了乙烯环氧化反应活住氧种的表面分布，对Ｃ_２Ｈ_４的环氧化反应有一定的抑制作用，但是对Ｃ２Ｈ４和ＥＯ的深度氧化反应的抑制作用更强，使得乙烯环氧化反应的选择性得到改善．     

偶合反应化学发光法测定痕量银的研究

本将Ａｇ（Ⅰ）催化Ｓ２Ｏ＾２－８氧化Ｍｎ（Ⅱ）生成ＭｎＯ＾－４的催化反应与ＬｕｍｉｎｏｌＭｎＯ＾－４－ＯＨ＾－的化学发光反应相偶合，建立起一种新的灵敏测定痕量银的化学发光分析法，在所研究的优化条件下，该法测定银的选择性较好，检测限达到３．２×１０＾－１２ｇ／ｍＬＡｇ线性浓度范围为１．０×１０＾－１１－１．０×１０＾－５ｇ／ｍＬＡｇ，用于水样分析，结果较为满意。     

Cu－Ag／γ－Al_2O_3催化剂的还原特性及对苯的氧化活性

Ｃｕ－Ａｇ／γ－Ａｌ_２Ｏ_３催化剂的还原特性及对苯的氧化活性朱波，陈平，罗孟飞，袁贤鑫（杭州大学化学系，杭州３１００２８）吴红丽（杭州大学中心实验室，杭州３１００２８）关键词Ｃｕ－Ａｇ／γ－Ａｌ_２Ｏ_３催化剂，还原特性，苯的完全氧化反应，氧化活性．１...     

活性碳纤维ZnO—SACF的制备及其对Ag^＋的氧化还原吸附

制备了含有ＺｎＯ的活性碳纤维ＺｎＯ－ＳＡＣＦ，借助ＡＡＳ，ＷＡＸＤ和ＳＥＭ探讨了ＺｎＯ－ＳＡＣＦ对Ａｇ＾＋的氧化还原吸附特性，并考察了ＺｎＯ在氧化还原中的作用。结果表明，ＺｎＯ－ＳＡＣＦ比ＳＡＣＦ具有对Ａｇ＾＋更高的氧化还原吸附量。外加ＺｎＯ的实验发现，ＺｎＯ本身并不吸附Ａｇ＾＋，但却参与氧化还原反应，中和氧化还原体系所释放出的Ｈ＾＋，提高了体系的ＰＨ值，可以认为，ＰＨ值的提高有利于ＳＡＣＦ电极电     

添加Ag对Cu／γ－Al_2O_3催化剂

运用ＢＥＴ、ＸＲＤ、ＴＰＲ及苯和丙酮氧化活性测定等方法研究了Ｃｕ／γ－Ａｌ_２Ｏ_３和Ｃｕ－Ａｇ／γ－Ａｌ_２Ｏ_３催化剂的还原性能和对有机物的催化活性。结果表明：不同金属负载量的Ｃｕ／γ－Ａｌ_２Ｏ_３催化剂的还原性能有明显差异，反映出催化剂表面存在着不同种类的铜物种。Ａｇ的添加使催化剂的ＴＰＲ峰位发生明显位移，提高了催化剂对有机物的催化氧化活性。同时还发现，热处理温度对催化剂中铜物种的存在形式、催化还原特性及催化活性有明显影响．Ａｇ在一定程度上提高了催化剂的热稳定性。     

Motion of redox molecules in solution monitored by the highly-sensitive EQCM technique

The behavior of redox molecules in solution that was not detected by electrochemical techniques was measured by a highly-sensitive electrochemical quartz crystal microbalance (EQCM) technique that has been improved in this study to obtain a high sensitivity of EQCM measurement in solution. The improved EQCM technique allowed to monitor the motion of a redox molecule, that is an access of the molecule to an electrode surface and repulsion from the surface during redox. An EQCM technique currently in use has measured adsorption of redox molecules on an electrode surface or polymerization on the surface caused by a chemical reaction following redox, which exhibits an enough large mass change response to detect with an EQCM measurement. However, access and repulsion of redox molecule, which is a slight motion of the molecule near on electrode surface, has not been detected and investigated by an EQCM technique, because the mass change response seems to be very small. In this study, the redox behavior of methyl viologen on a bare gold surface, pyridinethiol surface and methylpyridinethiol surface was investigated. Although the three electrodes give the same cyclic voltammogram of methyl viologen, the three are different in QCM response recorded at the same time as the voltammetry. Access/repulsion of methyl viologen within an electrical double layer was monitored by the highly-sensitive EQCM technique.     

Motion of redox molecules in solution monitored by the highly-sensitive EQCM technique

The behavior of redox molecules in solution that was not detected by electrochemical techniques was measured by a highly-sensitive electrochemical quartz crystal microbalance (EQCM) technique that has been improved in this study to obtain a high sensitivity of EQCM measurement in solution. The improved EQCM technique allowed to monitor the motion of a redox molecule, that is an access of the molecule to an electrode surface and repulsion from the surface during redox. An EQCM technique currently in use has measured adsorption of redox molecules on an electrode surface or polymerization on the surface caused by a chemical reaction following redox, which exhibits an enough large mass change response to detect with an EQCM measurement. However, access and repulsion of redox molecule, which is a slight motion of the molecule near on electrode surface, has not been detected and investigated by an EQCM technique, because the mass change response seems to be very small. In this study, the redox behavior of methyl viologen on a bare gold surface, pyridinethiol surface and methylpyridinethiol surface was investigated. Although the three electrodes give the same cyclic voltammogram of methyl viologen, the three are different in QCM response recorded at the same time as the voltammetry. Access/repulsion of methyl viologen within an electrical double layer was monitored by the highly-sensitive EQCM technique.     

Electrochemical deposition of poly(trans-[RuCl2(4-vinylpyridine)4]) and its reductive desorption: cyclic voltammetry and electrochemical quartz crystal microbalance studies

The electropolymerization of trans-[RuCl(2)(vpy)(4)](vpy = 4-vinylpyridine) on Au or Pt electrodes was studied by cyclic voltammetry and the electrochemical quartz crystal microbalance (EQCM) technique. Cyclic voltammetry of the monomer in DMSO on Au shows reductions at -2.0 and -2.2 V. Potential cycling over the first wave leads to polymer formation; however, scanning over the second wave leads to desorption of the polymer. These observations were confirmed by EQCM measurements which also revealed a high polymerization efficiency. Electrolysis, EQCM and XPS measurements showed that desorption was associated with substitution of chloride ligands by DMSO when the polymer was in a highly reduced state. The film also showed reversible mass changes due to the oxidation and accompanying ingress of charge-balancing anions and solvent into the film. Measurements on the dried films revealed that large quantities of solvent are trapped in the film during the electropolymerization process.     

Studies of the interfacial properties of an electroplated Sn thin film electrode/electrolyte using in situ MFTIRS and EQCM

Sn thin film electrodes were prepared by electroplating in an acidic sulfate bath containing SnSO4. During charge/discharge processes, the interfacial properties between a Sn thin film electrode and an electrolyte of 1 mol.L(-1) LiPF6 in a mixture of ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1 vol %) were investigated by using cyclic voltammetry (CV), electrochemical quartz crystal microbalance (EQCM), and in situ microscope Fourier transform infrared reflection spectroscopy (in situ MFTIRS). The processes of alloying/dealloying of lithium with Sn and the decomposition of the electrolyte on the Sn electrode were characterized quantitatively by surface mass change and at the molecule level. EQCM studies demonstrated that the mass accumulated per mole of electrons (mpe) was varied in different electrochemical processes. In the process of electrolyte decomposition, the measured mpe is smaller than the theoretical value, whereas it is higher than the theoretical value in the process of alloying/dealloying. The reduction products, ROCO2Li, of the electrolyte involved in charge/discharge processes were determined by in situ MFTIRS. The solvation/desolvation of lithium ion with solvent molecules, which is induced by the alloying/dealloying of lithium with Sn, was evidenced by shifts of relevant IR bands of C=O, C-O, and C-H. The current studies clearly revealed the details of interfacial reactions involved in lithium ion batteries employing a Sn thin film as the anode.     

The processes involved in the Se electrodeposition and dissolution on Au electrode: the H<Subscript>2</Subscript>Se formation

The processes involved in the Se electrodeposition, mainly the one related to the formation of H₂Se species on Au electrode in perchloric acid solutions, have been investigated through cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM), rotating ring-disc electrode (RRDE), and atomic force microscopy (AFM) techniques. In the experiments performed with the EQCM, with the potential sweep in the negative direction, the responses for the mass variation were divided in three well-defined potential regions: A (from 1.55 to 0.35 V), B (from 0.35 to −0.37 V), and C (from −0.37 to −0.49 V). It was verified that the following processes can occur, respectively: the species (AuO)₂H₂SeO₃ was desorbed during the AuO reduction, the reduction of Se(IV) to Se(0), and the formation of H₂Se. When the potential was swept in the positive direction, the responses for the mass variation were divided in four well-defined potential regions: D (from −0.49 to 0.66 V), E (from 0.66 to 0.99 V), F (from 0.99 to 1.26 V), and G (from 1.26 to 1.55 V), and the described processes in these regions were, respectively: the Se deposition and adsorption of water molecules and/or perchlorate ions, the Se dissolution, the Se incorporating mass in the form of HO–Se, and the Au oxidation (all potentials are referred to the Ag/AgCl electrode). Making use of the RRDE, using the collection technique, the formation of H₂Se species during the Se electrodeposition was investigated. Therefore, it was confirmed that this species is formed on the disc electrode between −0.3 and −0.55 V vs the Ag/AgCl potential range (collecting the oxidized compound onto the ring electrode). AFM images also indicated that the surface topography of the Se-massive deposit on Au is different from the images registered after the formation of H₂Se species, confirming the cathodic stripping of Se.     

铂基Pb-Sb表面合金电催化剂的制备与结构表征

通过电化学方法,在玻碳载体表面制备以Pt、Pb、Sb为主要成分的铂基Pb Sb表面合金电催化剂.运用电化学循环伏安、石英晶体微天平（EQCM）和扫描隧道显微镜（STM）技术对催化剂电极进行表征.结果表明：酸性溶液中在所制备的表面合金电极上,析氢起始电位负移至－0.45 V,表面合金的起始氧化电位为0.15 V,其稳定性明显高于电催化还原中常用的铅、锑等金属电极.通过EQCM研究表面合金电极的形成过程,结合STM观察和XPS深度剖析,确定电催化剂表面是由粒度均匀的纳米颗粒构成的表面合金层.     

Mediated oxidation of ascorbic acid on a homologous series of ferrocene-terminated self-assembled monolayers

The kinetics of electrocatalytic oxidation of ascorbate was studied on a series of redox self-assembled monolayers (SAMs) of the general formula Fc(CH2)4COO(CH2)nSH as electron-transfer mediators, where Fc is the ferrocenyl group and n = 3, 6, 9, and 11. We show that the rate of electron transfer from ascorbate to the surface-confined Fc+ decreases with increasing n. The rationale for the dependence of the rate of electrocatalytic activity and n, in the presence of ClO4, is obtained from Fourier-transform surface-enhanced Raman spectroscopy (FT-SERS), cyclic voltammetry, and electrochemical quartz crystal microbalance (EQCM) data. In particular, FT-SERS shows decreasing amounts of surface-bound ClO4- upon oxidation of the ferrocene with decreasing n, while EQCM data show the effective electrode mass increase was consistently higher on the shorter chain SAMs. This mass increase is likely due to increasing ferricinium cation hydration. As n decreases, the SAMs become less ordered (FT-SERS data), as is widely known from previous literature. Disorder favors water penetration into the SAM, which, in turn, increases the hydration of the Fc+ (EQCM data). Increased hydration of the Fc+ impedes the formation of Fc+-ClO4- ion pairs (EQCM and FT-SERS data), which, consequently, accelerates the electrocatalytic electron transfer from the solution-dissolved ascorbate.     

EQCM for In-depth Study of Metal Anodes for Electrochemical Energy Storage

Electrochemical quartz crystal microbalance(EQCM) is a powerful tool to study the mass change and charge transfer during electrochemical process. The mass change on the electrode surface can be monitored with high precision and high sensitivity, making it possible to analyze the in-depth mechanism of electrode reactions. The application of metal anodes has exhibited great potential for the future energy storage devices for the elevated capacity. Herein, we review the research progress utilizing EQCM for metal anodes, including the deposition/dissolution process, the side reactions, the effect of additives, etc. Furthermore, we also put forward a perspective on research of the mechanism and performance improvement of metal anodes.     

Underpotential Deposition and Stripping of Lead at Disorganized Monolayer‐Modified Gold Electrodes

Underpotential deposition (UPD) and stripping of Pb²⁺ at thiol‐based disorganized monolayer‐modified gold electrodes was studied by cyclic voltammetry (CV) and electrochemical quartz crystal microgravimetry (EQCM). Electrodes modified with mercaptoacetic acid or mercaptoethane sulfonic acid were studied. Due to the proximity of the potentials for the Pb UPD and thiol reductive desorption, achievement of a UPD‐stripping voltammetry methodology for determination of low concentrations of Pb²⁺ was not successful. However by comparison of the CV and EQCM data and consideration of the possible mass changes per mole electrons transferred in light of the other species present in solution, possible mechanisms are put forward for the deposition and stripping of Pb²⁺ at thiol‐modified electrodes.     

Electroless deposition of gold into poly-3,4-ethylenedioxythiophene films and their characterization performed in chloride-containing solutions

Au-containing polymer films were obtained by electroless deposition of gold from diluted solutions of HAuCl₄ into preliminarily reduced poly-3,4-ethylenedioxythiophene (PEDOT) films. Structural peculiarities of such pristine and composite films were characterized by scanning and transmission electron microscopy methods. It was established that the gold clusters forming under such deposition appear on the outer surface of polymer films and their pores. The clusters’ sizes ranged between 30 and 100 nm depending on the time of exposition of a PEDOT film in solutions of Au(III) ions and the concentration of these ions. It was also observed that in contrast to pristine PEDOT films, cyclic voltammograms (CVs) of composite films in the presence of chloride ions show additional redox peaks resulting from oxidation of gold with formation of an insoluble product and followed by the product reduction under reversal of the potential scan direction. As a result of parallel electrochemical quartz crystal microbalance (EQCM) and CV measurements, it was also established that the number of chloride ions per one transferring electron in the gold oxidation process is near to unity. To elucidate the oxidation degree of gold in the presence of chloride ions, a special procedure of changing the electrode potential was used. It consisted of clamping the high anodic potential in the region of gold oxidation (0.97 V, Ag/AgCl) and subsequent gradual decrease of the electrode potential with a constant scan rate. Under these conditions, it was possible to completely oxidize all the gold particles containing in a composite film and find out the maximum amount of electricity consumed for the product particles’ reduction. A comparison between such data and the results obtained in EQCM determinations of the gold content in the same film led to the conclusion that the oxidation state of gold in the complexes formed is Au(III). The effects of chloride ion concentration and scan rate of the electrode potential on current responses of PEDOT–Au films were investigated. Some primary conclusions on the kinetics of the studied processes are made.