一些不饱和有机酸在Pt-Rh合金电极上的吸附规律

采用快速动电位扫描方法,系统研究了吸附时间、溶液浓度、温度等因素对在不同组成的Pt-Rh电极上,不饱和有机酸吸附过程的影响.研究结果表明,在中等表面覆盖率下,所研究的不饱和有机酸在Pt-Rh合金电极上吸附速率都遵循罗金斯基-捷里达维奇方程v=(dθ′ R)/(dτ)=kcexp(-αf′θ′ R).Pt电极上吸附速率最大,从Pt电极向Rh电极过渡中,吸附速率下降20～30倍.温度升高吸附速率加快.丙烯酸在Pt-Rh电极表面的吸附速率比其他不饱和有机酸高,并按丙烯酸>丁烯酸>顺丁烯二酸顺序递减.

Adsorption behavior of some unsaturated aliphatic acids on Pt-Rh alloy electrodes

On Pt-Rh alloy electrodes, the effect of some operational parameters on the adsorption process of several unsaturated aliphatic acids was respectively examined by fast potentiodynamic cathode-polarization. As the experimental results shown, the adsorption rates of acrylic acid, crotonic acid and maleic acid, in the middle cov-erage, obey Rogynski-Zilidowicz equation:ν=dθ'_R/dτ=kcexp（-αf'θ'_R). Comparatively, the maximal values ofadsorption rate are determined on the pure Pt-electrode, and as the electrode binary xomposition is baried successibely from the pure Pt to Rh,the adsorption tates for these acids are generally decreased,even by 20-30 times.Among the three unsaturated aliphatic acids,acrylic acid is most adbantageously adsorbed on the electrode surfaces.The adssorprion activity order is acrylic acid>crotomic acid>maleic acid.