烟酸在铁钝化膜层表面的吸附机理(英文)  

Adsorption Mechanism of Nicotinic Acid onto a Passive Iron Surface

作　　者：田惠文[1,2] 李伟华[1] 王大鹏[3] 侯保荣[1] 

机构地区：[1]中国科学院海洋研究所,山东省腐蚀科学重点实验室,山东青岛266071 [2]中国科学院研究生院,北京100049 [3]青岛科技大学,教育部及山东省橡塑重点实验室,山东青岛266042

出　　处：《物理化学学报》2012年第1期137-145,共9页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China (51179182);Shinan Scientific and Technological R&D Foundation of Qingdao City, China (P2010-1-ZH-005);Ph.D. Foundation of Shandong Province, China (BS2009HZ002);K. C. Wong Education Foundation, Hong Kong, China (20061231)~~

摘　　要：循环伏安法结合原位拉曼光谱的表征结果表明,烟酸在铁钝化膜层表面的吸附行为归因于其具有形成稳定膜层复合物的性能,烟酸将间隙离子FeⅡ转化为稳定的晶格离子FeⅢ,从而降低铁钝化膜的溶解性.旋转电极电化学晶体微天平的分析结果表明烟酸在活化态和钝化态铁表面的吸附行为遵循Langmuir-Freundlich热力学规律,并由此计算出过程中的吸附常数、标准自由能和非均质分布常数.研究认为有机分子在钝化膜表面为化学型吸附,可导致钝化膜破坏的间隙离子被烟酸固定在八面体空位晶格中形成稳定晶型结构,并通过扫描电镜(SEM)和衰减全反射红外光谱(ATRFTIR)分析对结论进行了再次验证.Cyclic voltammetry and in situ Raman spectroscopy were used to determine the adsorption mechanism of nicotinic acid onto passive iron film surface.Its ability to form a surface complex tends to stabilize the interstitial FeⅡ in FeⅢ states and results in the progressive development of an insoluble film.Furthermore,an analytical investigation using a rotating electrochemical quartz crystal microbalance （rEQCM） showed that the adsorption isotherms of nicotinic acid onto iron in the active and passive states followed Langmuir-Freundlich behavior from which the adsorption constant,standard free energy of adsorption,and heterogeneity could be calculated.The organic molecules attach to the film surface by chemisorption and the interstitial cations are fixed in the octahedral sites giving stable nanocrystals.These assumptions were confirmed by scanning electron microscopy （SEM） and attenuated total reflection transform infrared （ATR FTIR） spectroscopy.

关 键 词：烟酸 铁钝化膜 碱性介质 吸附 

分 类 号：O647.32[理学—物理化学]