Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (01): 137-145.doi: 10.3866/PKU.WHXB201228137

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Adsorption Mechanism of Nicotinic Acid onto a Passive Iron Surface

TIAN Hui-Wen1,2, LI Wei-Hua1, WANG Da-Peng3, HOU Bao-Rong1   

  1. 1. Key Laboratory of Corrosion Science in Shandong, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, Shandong Province, P. R. China;
    2. Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. China;
    3. Key Laboratory of Rubber-Plastics of Ministry of Education and Shandong Province, Qingdao University of Science & Technology, Qingdao 266042, Shandong Province, P. R. China
  • Received:2011-06-30 Revised:2011-10-11 Published:2011-12-29
  • Contact: LI Wei-Hua
  • Supported by:

    The project was 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), and K. C.Wong Education Foundation, Hong Kong, China (20061231).

Abstract: 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 Fe in Fe 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.

Key words: Nicotinic acid, Passive film on iron, Alkaline medium, Adsorption


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