PT电极上β-丙氨酸吸附和氧化过程的CV和原位EQCM研究

应用电化学循环伏安和原位电化学石英晶体微天平(EQCM)方法研究了0．1mol．L^-1硫酸溶液中β—丙氨酸在Pt电极上的吸附和氧化过程。结果表明：0．1mol．L^-1硫酸溶液中氢脱附电位区间内电极表面质量的增加是由于水分子取代Had引起的，而双电层区的质量增加是由于水的吸附模式逐渐由氢端吸附转向氧端吸附所致,根据频率变化和电量数据，可进一步推算出酸性溶液中β—丙氨酸在Pt电极表面只发生弱吸附，水和β—丙氨酸阴离子都可以取代部分氢，吸附在电极表面，影响了电极表面质量的变化量，而吸附态β—丙氨酸在高电位氧化时会消耗Pt表面的氧。本文结果为认识β—丙氨酸在Pt电极表面过程提供定量的新数据。

Studies of Adsorption and Oxidation of β-Alanine on Pt Electrode Using CV and EQCM

The processes of adsorption and oxidation of P-Alanine in acidic solution on Pt Electrode were studied by cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). Quantitative analysis of the mass change on the surface of electrode revealed that the increase of mass in the hydrogen region in a positive-going potential scan is caused by the substitution of Had by water molecule, while in double-layer region this is due to the conversion of binding mode of water from hydrogen-terminal to oxygen-terminal. According to data of the frequency variation and electric quantity, H2O and P-Alanine anion can substituted the adsorbed hydrogen, inhibit the desorption of part of hydrogen and influence the degree of mass variation. The adsorbed P-Alanine during its oxidation can consume the adsorbed oxygen. The EQCM studies provided quantitative results of surface mass variation during P-Alanine oxidation, and have thrown new light in elucidating surface process and reaction mechanism of adsorption and oxidation of small amino acids on Pt electrode.