不同介质中甲醛在Au_(core)@Pt_(shell)/Pt电极上氧化的原位SERS研究

应用化学还原法合成了Aucore@Ptshell纳米粒子,并用扫描电子显微镜(SEM)和能量色散光谱(EDS)对其进行了表征;采用电化学原位表面增强拉曼散射(SERS)光谱技术研究了不同介质中甲醛在Aucore@Ptshell/Pt电极上的电催化氧化行为,获得了不同介质中甲醛在Aucore@Ptshell/Pt电极上电催化氧化行为的原位SERS谱.研究结果表明,不论在酸性、中性还是碱性介质中,甲醛均能在Aucore@Ptshell/Pt电极上自发氧化解离出强吸附中间体CO,只是在碱性介质中桥式吸附CO的比例明显增大,且桥式吸附比线形吸附CO更易被氧化,使CO在碱性介质中基本氧化完毕的电位比在中性及酸性介质中提前了约950 mV.分子水平的研究结果表明,CO和甲醛在碱性介质中比在中性和酸性介质中更易被氧化

In situ Surface-Enhanced Raman Spectroscopic Investigation of Formaldehyde Oxidation on Au-core@Pt-shell Nanoparticles Coated Platinum Electrode in Different Media

Au-core@Pt-shell nanoparticles were synthesized by chemical reduction method. The samples were characterized by scanning electron microscope( SEM ) and energy dispersive spectroscopy ( EDS ). In situ surface-enhanced Raman spectroscopy( SERS ) was utilized to investigate the electro-oxidation behavior of formaldehyde in different media adsorbed on Au-core@Pt-shell nanoparticles coated platinum electrode. Surface-enhanced Raman scattering spectra with high quality were acquired. The results show that formaldehyde can dissociate spontaneously to produce strongly adsorbed intermediate, CO, in acidic, neutral, and alkaline media on a Au-core@Pt-shell nanoparticles coated platinum electrode. However, the bridge adsorbed CO were increased more significantly in alkaline media. In addition, the bridge adsorbed CO could be oxidized more easily than the linear adsorbed CO. The Raman signal of CO disappeared at -0. 4 V in alkaline media, it shifted negatively about 950 mV than in acidic or neutral media. The study demonstrates that Au-core@Pt-shell nanoparticles coated on platinum substrate as electrode exhibited better electrocatalytic properties for the oxidation of formaldehyde in alkaline media than in acidic or neutral media