科研之友
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摘要
Fe-III-substituted phosphorous heteropolytungstate anion PW11O39FeIII(H2O)(4-) (PW11Fe) is an excellent electrocatalyst for single electron reduction in aqueous medium. How to immobilize it on an electrode is important for practical applications and has been receiving one's efforts. The paper reports a novel crystal-modified electrode (CME) Bu4NPW11Fe/C, which was prepared by immobilizing the tetrabutylammonium salt of PW11Fe (Bu4NPW11Fe) on the surface of a graphite electrode using a simple hydrothermal process. After characterization by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) etc., the electrochemical behavior and electrocatalytic activity towards H2O2 reduction of this CME were studied using the electrochemical methods of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the Bu4NPW11Fe crystals grew on the surface of the graphite electrode in the form of polycrystals such as cube, dodecahedron, and rod shape. The size of the crystalline particles varied from 0.7 to 10.4 mu m. The as-prepared CME still retained the electrochemical property of PW11Fe in homogeneous solution. More importantly, it exhibited a better electrocatalytic performance for H2O2 reduction than the modified electrode PW11Fe/CS/C reported previously, prepared by a sol-gel process using chitosan (CS) as an adsorbent. Thus, this research provides a simple and convenient strategy to prepare free-adsorbent and free-crosslinking agent-modified electrodes based on polyoxometalates.
