In Situ FTIR Spectrocopic Studies of CO and CN~- Adsorbed on Electrode of Nanometer Thin Film of Palladium in Alkaline Solutions

以原位FTIR反射光谱研究碱性介质中CO和CN-在纳米Pd膜电极上的吸附和共吸附 ,进一步揭示了纳米薄膜材料的异常红外效应和CO与CN-共吸附时的相互作用规律。The adsorption and coadsorption of CO and CN- - on electrode of nanometer thin film of palladium (nm-Pd/GC)was studied by usin g in situ FTIR spectroscopy.The results demonstrated that the nm-Pd/GC electrod e exhibited abnormal infrared effects (AIREs) in alkaline solutions as in acid s olutions.The characters of AIREs,i.e.,the inversion of the direc tion of IR band,the augmentation of FWHM and the significant enhancement of IR a bsorption by adsorbed species were observed in all cases of adsorption and coads orption of CO and CN--.It has been illustrated that strong interaction is exis ted between adsorbed CO and CN-- on nm-Pd/GC surface.The study has contribute d towards understanding the surface processes of chemisorption as well as to rev eal the origin of nanometer size-effects of thin film materials.国家自然基金!(2 98330 60 );; 教育部博士点基金!(1 9990 3840 3)资

纳米薄层Pt-Ru及Pt-Pd表面合金电极上CO吸附的原位FTIR研究

以玻碳为基底 ,通过电化学共沉积的方法制备纳米级厚度的表面合金电极 ,运用电化学原位红外反射光谱研究CO的吸附 .结果表明 ,所制备的PT ru和PT Pd纳米级厚度的表面合金电极均具有异常红外效应 ,即吸附在不同表面位上的CO给出的红外谱峰强度增强 ,其方向与相应金属电极表面获得的谱峰方向相反 .研究还显示PT ru和PT Pd表面合金在电催化和表面研究中的重要意义国家自然科学基金!(批准号:29833060)资助项

In situ FTIR spectrocopic studies of CO and CN- adsorbed on electrode of nanometer thin film of palladium in alkaline solutions

The adsorption and coadsorption of CO and CN- on electrode of nanometer thin film of palladium (nm-Pd/GC)was studied by using in situ FTIR spectroscopy. The results demonstrated that the nm-Pd/GC electrode exhibited abnormal infrared effects (AIREs) in alkaline solutions as in acid solutions. The characters of AIREs, i.e.,the inversion of the direction of IR band, the augmentation of FWHM and the significant enhancement of IR absorption by adsorbed species were observed in all cases of adsorption and co-adsorption of CO and CN-. It has been illustrated that strong interaction is existed between adsorbed CO and CN- on nm-Pd/GC surface. The study has contributed towards understanding the surface processes of chemisorption as well as to reveal the origin of nanometer size-effects of thin film materials

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

In situ FTIR Spectroscopic Investigations of Abnormal InFrared Properties of Absorption of CO and SCN--- on Dispersed Pt and Pd SurFaces

在玻碳基底上沉积PT和Pd，在以CO和SCn-为探针分子的电化学现场fTIr反射光谱研究中，首次观察到异常红外光学行为，其中包括吸附物种的谱带方向倒反以及谱峰强度显著增强等.The in situ molecular-probe FTIR spectroscopy was employed in the present workto study the adsorption of CO and SCN- on surFaces of dispersed Pt and Pd thin layers,which were deposited electrochemically on glassy carbon (denoted as Pt/GC and Pd/GC)uner voltanmmetric conditions.Abnormal IR Features of adsorption of CO and SCN- andPt/GC and Pd/GC have been observed For the First time.In comparison with IR Features ofadsorption of these molecules on smooth Pt and Pd electrodes, the abnormal IR Featuresconsist of mainly the inversion of the direction of IR band and the enhancement of bandintensities.The enhancement Factors were evaluated at 20 For linearly bonded CO on the Pt/GCsurFace anal at 26 For bridge bonded CO on the Pd/GC surFace.Nevertheless other spectralFeatures(the vibrational Frequency, the Stark eFFects, etc.) are nearly the same as thoseobserved on smooth Pt and Pd electrodes, and no signiFicant diFFerence in IR Features presentedFor adsorption of solution species (CO2, SCN- ) on the dispersed surFaces.The surFaceroughness of these dispersed electrodes was measured relatively small (1.6 For Pt/GC and 1.2For Pd/GC).The present study discovered an interesting IR property of dispersed metallicthin layers, and suggested that the in situ iR spectra of larger signal to noise ration may beobtained by employing the specially prepared Pt/GC and Pd/GC electrodes.国家自然科学基

Particular Properties and Structure of Electrochemically Prepared Pd Film Nano materials

用循环伏安方法制备纳米钯膜电极,运用扫描隧道显微镜和原位红外光谱等方法研究其结构和反应性能.STM图像表明,制备的纳米钯膜具有特殊的层状结构,纳米级厚度的层状晶体由直径6nM左右的Pd微晶聚集而成.发现当钯膜厚度为几个纳米时,CO的吸附表现出异常红外效应,即红外谱峰反向和红外吸收显著增强(增强因子可达42.6).纳米钯膜电极对氢的反应也具有特殊的性能,与氢向钯晶格扩散吸收过程相比较,氢吸脱附的表面过程成为主要反应.研究结果还指出,纳米钯膜电极的异常红外效应和对氢反应的特殊性能与钯膜厚度密切关联,并可归结为钯膜材料的纳米尺度效应.The Pd film nano materials supported on glassy carbon (nm Pd/GC) were prepared under conditions of electrochemical voltammetry.STM images illustrated that the Pd film consists of crystallites which are composed of nano particles of Pd with average size at around 6nm,and are of layer shapes.CO adsorption on nm Pd/GC electrodes manifested abnormal infrared effects (AIREs),i.e.,the inversion of IR band direction and the enhancement of IR absorption.In comparison with CO adsorption on massive Pd electrode,an enhancement factor at 42.6 was measured on a nm Pd/GC electrode of film thickness at 12.2nm.The nm Pd/GC electrode possesses particular properties for hydrogen reaction.It was revealed that,in contrast to hydrogen absorption by massive Pd electrode,the surface processes of hydrogen adsorption desorption become the dominant reaction on nm Pd/GC electrodes.The results demonstrated also that both the AIREs for CO adsorption and the particular properties for hydrogen reaction depend strongly on the thickness of Pd film,and can be consequently assigned to the nanometer size effect of Pd film materials.The present study has introduced important significance for further studies on surface electrochemistry and electrocatalysis.国家自然科学基

Studies of Abnormal Infrared Effects of Nanometer Thin Films of Transition Metals and Alloys in Acid Solutions

以循环伏安方法在玻碳载体上制备纳米级厚度的过渡金属 (Pt,Pd ,Rh ,Ru)和合金 (PtPd ,PtRu)薄膜电极 ,并运用原位FTIR反射光谱研究了CO的吸附过程 .发现所制备的纳米薄膜电极均具有异常红外效应 ,即与本体金属电极相比较 ,吸附在纳米薄膜电极上的CO分子的红外吸收被显著增强 ,并且红外谱峰方向倒反 .本文的结果进一步证明异常红外效应是一种新的、普遍的现象 ,主要取决于过渡金属或合金膜的结构和厚度 .对异常红外效应的深入认识 ,不仅将推动红外反射光谱及界面电化学理论的发展 ,而且将在表面和界面分析中得到广泛应用 .The adsorption of CO on electrodes of nanometer thin films of transition metals (Pt, Pd, Rh, Ru) and alloys (PtPd, PtRu) prepared under cyclic voltammetric conditions has been studied by in situ FTIR spectroscopy. The abnormal infrared effects (AIREs) have been explored as a novel and general phenomenon. The AIREs consist mainly in the inversion of the direction of IR band and the significant enhancement of IR absorption by adsorbed CO species. It was revealed that the enhanced IR absoroption of adsorbed species in AIREs depends strongly on the nature of metal or alloy, and on the structure and the thickness of the thin film. The investigation of AIREs will contribute not only to develop the theory of reflectance IR spectroscopy as well as interfacial electrochemistry, but also to increase the determining sensitivity in applications of interfacial and surface analysis.作者联系地址：厦门大学固体表面物理化学国家重点实验室!化学系,物化所,福建厦门361005,厦门大学固体表面物理化学国家重点实验室!化学系,物化所,福建厦门361005,厦门大学固体表面物理化学国家重点实验室!化学系,物化所,福建厦门361005,厦门大学固体表面物理化学国家重点实验室!化学系,物化Author's Address: State key Lab. For Phys.Chem. of Solid Surfaces, Dept. of Chem., Institute of Phys.Chem.,Xiamen University, Xiamen 361005,Chin

乙烯与甲苯乙基化制对甲基乙苯反应用沸石催化剂

一种用于甲苯与乙烯进行烷基化反应，特别是适宜用于低浓度乙烯为原料的甲苯烷基化反应过程所用含有锑（或磷）及镁元素化学改质处理的Ｐｅｎｔａｓｉｌ型硅铝沸石催化剂。这种沸石催化剂可以直接用含有硫化氢、水等杂质的炼油厂尾气（含乙烯１０－２０％）作原料与甲苯反应制取主要为对位甲基乙苯的过程。与以纯乙烯为原料的甲苯烷基化反应进程相比，当直接采用含杂质的低浓度乙烯的炼油厂尾气为原料时，本发明的沸石催化剂具有良好的反应性能。带填