Studies on the reduction of birnessite thin layers: Influence of medium
Studies on the reduction of birnessite thin layers: Influence of medium
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DOI：
10.1016/j.electacta.2011.07.054
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发表时间：
2011-10
影响因子：
6.6
通讯作者：
M. Ndjeri;S. Peulon;S. Bach;A. Chaussé
中科院分区：
文献类型：
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作者：
M. Ndjeri;S. Peulon;S. Bach;A. Chaussé
本文描述了在中性硫酸盐溶液中，电沉积在廉价透明半导体衬底二氧化锡（SnO2）上的硼硅矿薄层的还原研究。基于电化学测量（循环伏安法和计时安培法）和x射线衍射（XRD）表征的耦合方法使我们能够给出在溶液中存在或不存在Mn（II）时铋矿还原机制的信息。在没有Mn（II）的情况下，如果q还原低于q合成，则birnite仅在低电位（E= - 0.6V）下还原为β-MnOOH (feitkneichite)，如果q还原等于q合成，则在无定形Mn（II）化合物中。溶液中有Mn（II）存在时，检测到hausmannite (Mn3O4)，即使在高电位（E=0.15V）下也能检测到。这些结果表明，Mn（III）与溶液中Mn（II）的还原可以在表面附近形成配合物，形成Mn3O4，这是一种非常电阻的化合物。这些结果对于致力于环境应用、化学传感器和能量存储的研究具有重要意义。
This paper describes studies on the reduction of birnessite thin layers electrodeposited onto a cheap transparent semiconductor substrate, tin dioxide (SnO2), in neutral sulphate solutions. A coupled approach based on electrochemical measurements (cyclic voltammetry and chronoamperometry) and X-ray diffraction (XRD) characterisation allowed us to give information about reduction mechanism of birnessite in presence or absence of Mn(II) in solution. In absence of Mn(II), birnessite is reduced only at low potential (E=−0.6V) into β-MnOOH (feitkneichtite), if Qreductionis lower than Qsynthesis, and in amorphous Mn(II) compound, if Qreductionis equal to Qsynthesis. In presence of Mn(II) in solution, hausmannite (Mn3O4) was detected, and even at high potentials (E=0.15V). These results signify that a complex between Mn(III), coming from the reduction of Mn(IV) species, and Mn(II) present in solution, can be formed near the surface and leads to the formation of Mn3O4, a very resistive compound. These results are important for studies devoted to environmental applications, chemical sensors and also for energy storage.