Sitnikova Natalya A, Komkova Maria A, Khomyakova Irina V, Karyakina Elena E, Karyakin Arkady A
Department of Chemistry, M.V. Lomonosov Moscow State University , 119991, Moscow, Russia.
Anal Chem. 2014 May 6;86(9):4131-4. doi: 10.1021/ac500595v. Epub 2014 Apr 15.
The ability of Prussian Blue, ferric hexacyanoferrate (FeHCF), to sensitively and selectively detect hydrogen peroxide by its reduction in the presence of oxygen is of high importance for analytical chemistry. Success with Prussian Blue (PB) provided an appearance of contradictory reports concerning electrocatalysis of the other transition metal hexacyanoferrates (HCFs) in H2O2 reduction. Investigating thermodynamics of the catalyzed reactions as well as electrochemical properties of the hexacyanoferrates, we are able to conclude that the noniron hexacyanoferrates themselves are completely electrocatalytically inactive, except for a minor electrocatalysis in the opposite reaction, hydrogen peroxide oxidation, registered for NiHCF. Concerning the most important reaction, H2O2 reduction, the observed electrocatalytic activity (by the way, 100 times decreased compared to PB) is due to the presence of FeHCF (Prussian Blue) as defects in the structure of noniron hexacyanoferrates. This finding, considering other unique properties of transition metal HCFs, will provide a systematic search for sensing materials with improved analytical performance characteristics.
普鲁士蓝，即六氰合铁酸铁（FeHCF），在有氧存在的情况下通过还原作用灵敏且选择性地检测过氧化氢的能力，对分析化学而言至关重要。普鲁士蓝（PB）取得的成功引发了关于其他过渡金属六氰合铁酸盐（HCFs）在过氧化氢还原反应中的电催化作用的相互矛盾的报道。通过研究催化反应的热力学以及六氰合铁酸盐的电化学性质，我们能够得出结论，除了在相反反应（即过氧化氢氧化反应）中观察到镍六氰合铁酸盐（NiHCF）有轻微电催化作用外，非铁六氰合铁酸盐本身完全没有电催化活性。关于最重要的反应——过氧化氢还原反应，观察到的电催化活性（顺便说一下，与PB相比降低了100倍）是由于非铁六氰合铁酸盐结构中存在作为缺陷的FeHCF（普鲁士蓝）。考虑到过渡金属HCFs的其他独特性质，这一发现将有助于系统地寻找具有改进分析性能特征的传感材料。
