In Situ FTIR Studies of CO Adsorption on Palladium Loading Zeolite Elec trode

制备载Pd的分子筛电极 ,以CO吸附为探针结合电化学原位FTIR反射光谱 ,首次发现限定在分子筛超笼中的纳米Pd微粒对CO的吸附具有增强红外吸收效应。Adsorption of CO on palladium loading zeolite el ectrode supported on Pt or GC substrate was studied by in situ MSFTIR spectrosco py.The results demonstrated that the geometry of faujasite supercages favors the formation of bridge-bonded CO species.The enhanced IR adsorption of CO adsorbe d on Pd clusters located in the supercages of zeolite has been observed for the first time,which is a new phenomenon and differs from the abnormal infrared effe cts discovered by our group and the surface enhanced infrared absorption phenome non reported in the literature.国家自然科学基金资助项目!(2 99730 35

In Situ FTIR Spectrocopic Investigations of 1,3-Butanediol Oxi dation on Sb and S Modified Pt Electrodes

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。In the present paper,we studied the surface st ru cture effect of Pt electrode modified with antimony and sulfur adatoms towards 1 ,3-Butanediol oxidation.The results demonstrated that the modification of Sb an d S both inhibited the dissociative adsorption of 1,3-Butanediol into CO,which is the main source of self-poisoning in electrocatalysis of small organic molec ules.At lower potentials,the principal oxidation pathway of 1,3-Butanediol on P t/Sb ad electrode is towards the production of C=O.However,at higher potent ials,the products of CO 2 increased.The presence of S ad inhibited the ox idation of 1,3-BD at low potentials(0 8 V).国家自然基金!(2 99730 35)资

In situ FTIR studies of CO adsorption on palladium loading zeolite electrode

Adsorption of CO on palladium loading zeolite electrode supported on Pt or GC substrate was studied by in situ MSFTIR spectroscopy. The results demonstrated that the geometry of faujasite supercages favors the formation of bridge-bonded CO species. The enhanced IR adsorption of CO adsorbed on Pd clusters located in the supercages of zeolite has been observed for the first time, which is a new phenomenon and differs from the abnormal infrared effects discovered by our group and the surface enhanced infrared absorption phenomenon reported in the literature

In situ FTIR spectrocopic investigations of 1,3-butanediol oxidation on Sb and S modified Pt electrodes

In the present paper,we studied the surface structure effect of Pt electrode modified with antimony and sulfur adatoms towards 1,3-Butanediol oxidation. The results demonstrated that the modification of Sb and S both inhibited the dissociative adsorption of 1,3-Butanediol into CO, which is the main source of self-poisoning in electrocatalysis of snail organic molecules. At lower potentials,the principal oxidation pathway of 1,3-Butanediol on Pt/Sb-ad electrode is towards the production of C = O. However,at higher potentials,the products of CO2 increased. The presence of S-ad inhibited the oxidation of 1,3-BD at low potentials(0.8 V)

Kinetics of Irreversible Reactions on Platinum Single Crystal Electrodes─-Ⅰ. in situ FTIR Spectroscopic Studies of Formic Acid Oxidation on Pt(100) Electrode

运用电化学暂态方法和现场时间分辨fTIr反射光谱研究甲酸在PT（100）单晶电极上的解离吸附和氧化过程.深入认识了甲酸解离吸附的反应速率在-0.25至0.25V电位区间呈火山形变化的规律.根据电化学现场时间分辨红外光谱的研究结果，提出在研究反应动力学时避免甲酸解离吸附干扰的方法，为进一步研究甲酸在PT（100）电极表面经活性中间体直接氧化至CO2的反应动力学奠定了基础.The dissociative adsorption and oxidation of Formic acid on Pt(100) single crystalelectrode were investigated by using electrochemical techniques and in situ time resolved FTIRspectroscopy (TR-FTIRS).The results demonstrated that the distribution of the rate of dissociative adsorption of HCOOH on Pt(100) versus electrode potential yields a volcanic relationshipbetween -0.25 and 0.25 V.Based on results of TR-FTIRS, we concluded that the dissociative adsorption of HCOOH on Pt(100) can be avoided by designing appropriate potential step program,which is the basis of Further studies of the kinetics of direct oxidation of HCOOH into CO2 viareactive intermediates.国家杰出青年科学基金;国家教委博士点专项基

Kinetics of Irreversible Reactions on Platinum Single Crystal Electrodes(Ⅲ)

在本系列研究论文Ⅰ[1]和Ⅱ[2]报导的结果基础上，进一步发展动力学数据解析方法.通过改变反应体系的温度，首次获得甲酸在PT（100），PT（110），PT（111）电极上直接氧化反应的表观活化gIbbS自由能（△g≠0）.在实验选定的标准状态下，即0.0V/SCE、298.15k和1.013x105PA下，来算得到。还发现传递系数β在实验温度范围（283.15~303.15k）不随温度变化，但随电极表面原子排列结构变化，大小次序与△g≠0的变化一致.Based on results of the lst and 2nd papers of the present studies, the procedure of data processing was developed Further.Through the variation of the temperature of the reaction system the apparent Gibbs Free energy of activation (△G≠0) For direct oxidation of HCOOH on Pt(100),Pt(111) aud Pt(110) single crystal electrodes was obtained For the First time.Under the standard states deFined in the present study i.e, at 0.0V/SCE.298.15K alld 1.013×105Pa, the apparent Gibbs Free energy of activatiou For HCOOH oxidation has been evaluated as 32.2±0.5 kJ.mol-1 on Pt(100), 25.8±0.4 kJ·mol-1 on Pt(111) and 10.1±0.2 kJ·mol-1 on Pt(110), respectively.It has been Found that the transFer coeFFicieut (β) of HCOOH oxidation is independent of temperature in the range between 283.15 -- 303.15K, but varies with the surtace atomc arrangement of Pt siugle crystal electrode and yields the same variation order as that of the apparent Gibbs Frec energy of activation.国家自然科学基

Kinetics of Irreversible Reactions on Platinum Single Crystal Electrodes II. Data Processing and Kinetics Parameters for HCOOH Oxidation on Pt(100) Electrode

The kinetics of electrooxidation of HCOOH on Pt(100) via reactive intermediates was studied by using programmed step technique, which avoided successfully the interference of self-poisoning. A new data processing method was established based on the transform of integration of digital data recorded in electrochemical transient experiments, and the computer software developed for this method allowed us to obtain quantiatively, for the first time, the kinetics parameters of HCOOH oxidation on Pt(100) electrode. The results demonstrated that in a narrow potential range of 0.02 V to 0.15 V, the rate constant k(f) being varied from 9.510x10(-4) to 1.38x10(-2)cm.s(-1) and the relationship between In(k(f)) and E being a straight line. The transfer coefficient (beta) was calculated at 0.309, and the diffusion coefficient (D) of HCOOH in 5x10(-3) mol.L-1 HCOOH + 0.5 mol.L-1 H2SO4 solution was evaluated at 1.80x10(-5) cm(2).s(-1)

Kinetics of Irreversible Reaction on Platinum Single Crystal Electrodes

The dissociative adsorption and oxidation of formic acid on Pt(100) single crystal electrode were investigated by using elect heniical techniques and in situ time resolved FTIR spectroscopy (TR-FTIRS), The results demonstrated that the distribution of the rate of dissociative adsorption of HCOOH on Pt(100) versus electrode potential yields a volcanic relationship between 0.25 d 0,25 V. Batted on results of TR-FTIRS, we concluded that the dissociative adsorption of HCOOH on Pt (100) can be a avoided by designing appropriate potential step program, winch is the basis of further studies, of the kinetics of direct oxidation of HCOOH into CO2 via reactive intermediates

In Situ Time-resolved FTIR Studies of HCOOH Oxidation on Pt(100)/Sb Electrodes

以电化学原位时间分辨FTIR反射光谱和循环伏安方法研究甲酸在不同Sb覆盖度修饰的Pt(10 0 )单晶电极上的氧化。发现Sbad的修饰抑制了甲酸的解离吸附 ,使反应经活性中间体直接氧化至CO2 。电化学和红外光谱数据表明 ,θSb =0 2 4的Pt(10 0 ) /Sb电极具有最高的电催化活性The electrocatalytic oxidation of formic acid on Pt(100)/Sb electrodes of different coverage of Sb was investigated by using electrochemical techniques and in situ time resolve FTIRS.The results demonstrated that the diessociative adsorption of formic acid was inhibited by the presence of Sb ad on Pt(100) surface,as a consequence HCOOH can be oxidized directly into CO 2 via reactive intermediates.The rate of oxidation of formic acid varied with the coverage of Sb ad .It was revealed that at a Sb ad coverage of 0 24 the Pt(100)/Sb electrode exhibited the highest electrocatalytic activity for HCOOH oxidation.国家自然科学基金资助课题!( 2 99730 35

Study of Electropolymerization of o Phenylenediamine and Redox Process of Polymer Films

用循环伏安法和电化学石英晶体微天平（EQCM） 研究了0-1 MOl/lH2SO4 溶液中邻苯二胺在金电极上的电化学聚合过程及聚合膜（POPd） 的电化学性质. 邻苯二胺的起始氧化电位约为0-4 V（ VS-SCE） . 从EQCM 数据得知在酸性水溶液中邻苯二胺较易发生聚合，在邻苯二胺单体氧化的同时电极上就有聚合物沉积引起表面质量增加. 质子在POPd 膜氧化还原过程中起着非常重要的作用，POPd 膜质子化（ 氧化） 或去质子化（ 还原） 的同时使阴离子嵌入膜中或脱出，使EQCM电极频率发生变化，根据SAuErbry 方程计算了阴离子迁嵌入或迁脱出量及其随POPd膜质量和电位扫描速度的变化.The electropolymerization of o phenylenediamine(OPD) on gold electrode and the redox behavior of poly( o phenylenediamine)(POPD) films in sulfuric acid solutions have been studied by cyclic voltammetry and electrochemical quartz crystal microbalance(EQCM).The decrease in the resonant frequency of the quartz crystal during electropolymerization of OPD demonstrated that the deposition of the polymer films occurrs mainly in the potential range >0 5 V, at which the monomers are anodically oxidized.It is revealed that the protonation and deprotonation play an important role in the redox process of POPD films.The protonation during the reduction of POPD film induces the intercalation of anions, whereas the deprotonation in the oxidation of POPD film makes the escape of anions from the film.The quantity of anions intercalated into POPD film has been calculated according Sauerbry equation from the frequency decrease of EQCM electrode.Its values are in the range of 10 -9 to 10 -8 mol/cm 2 and varies with the mass of POPD film as well as with the scan rate of electrode potential.国家自然科学基