物理化学学报
物理化學學報
물이화학학보
ACTA PHYSICO-CHIMICA SINICA
2001年
2期
134-139
,共6页
表面合金%Sb-Pb-Pt/GC%EQCM%STM%XPS
錶麵閤金%Sb-Pb-Pt/GC%EQCM%STM%XPS
표면합금%Sb-Pb-Pt/GC%EQCM%STM%XPS
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-0.45V,表面合金的起始氧化电位为0.15V,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.
通過電化學方法,在玻碳載體錶麵製備以Pt、Pb、Sb為主要成分的鉑基Pb-Sb錶麵閤金電催化劑.運用電化學循環伏安、石英晶體微天平(EQCM)和掃描隧道顯微鏡(STM)技術對催化劑電極進行錶徵.結果錶明:痠性溶液中在所製備的錶麵閤金電極上,析氫起始電位負移至-0.45V,錶麵閤金的起始氧化電位為0.15V,其穩定性明顯高于電催化還原中常用的鉛、銻等金屬電極.通過EQCM研究錶麵閤金電極的形成過程,結閤STM觀察和XPS深度剖析,確定電催化劑錶麵是由粒度均勻的納米顆粒構成的錶麵閤金層.
통과전화학방법,재파탄재체표면제비이Pt、Pb、Sb위주요성분적박기Pb-Sb표면합금전최화제.운용전화학순배복안、석영정체미천평(EQCM)화소묘수도현미경(STM)기술대최화제전겁진행표정.결과표명:산성용액중재소제비적표면합금전겁상,석경기시전위부이지-0.45V,표면합금적기시양화전위위0.15V,기은정성명현고우전최화환원중상용적연、제등금속전겁.통과EQCM연구표면합금전겁적형성과정,결합STM관찰화XPS심도부석,학정전최화제표면시유립도균균적납미과립구성적표면합금층.
The electrocatalysts of platinum based Pb-Sb surface alloy were prepared by electrochemical codeposition under cyclic voltammetric conditions. The structure and properties of these electrocatalysts were studied by techniques of cyclic voltammetry,electrochemical quartz crystal microbalance(EQCM),scanning tunneling microscopy(STM) and X-ray photoelectron spectroscopy(XPS). The results demonstrated that the hydrogen evolution on the prepared electrocatalyst was postponed to - 0.45 V. i.e.,200 mV has been shifted negatively in comparison with hydrogen evolution at a platinum electrode. In addition,the oxidization of Pb and Sb components in surface alloy was positively shifted to above 0.15 V,which is much higher than the oxidization potential of Pb and Sb metal electrodes. The stability of surface alloy electrode is confirmed to be higher than Pb and Sb metal electrodes that were employed often in organic electrosynthesis. The process of formation of surface alloy was studied in situ by using an EQCM and ex situ by using a STM. The results have converged to illustrate that the surface alloy is constructed of nanoparticles with regular size of about 10 nanometers.The EQCM analysis and XPS depth profiling indicated that the surface alloy is formed on the top layer of a few nanometers in thickness of the Sb-Pb-Pt/GC electrode.