Catalytic activity of dual catalysts system based on nano-manganese oxide and cobalt octacyanophthalocyanine toward four-electron reduction of oxygen in alkaline media
Catalytic activity of dual catalysts system based on nano-manganese oxide and cobalt octacyanophthalocyanine toward four-electron reduction of oxygen in alkaline media
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DOI：
10.1016/j.electacta.2007.02.060
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发表时间：
2007-05
影响因子：
6.6
通讯作者：
Dun Zhang;Dahe Chi;T. Okajima;T. Ohsaka
中科院分区：
文献类型：
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作者：
Dun Zhang;Dahe Chi;T. Okajima;T. Ohsaka
研究了由电解纳米氧化锰（nano-MnOx）和八氰眼青碱钴（CoPcCN）组成的双功能催化剂体系对碱性介质中氧（O2） 4电子还原的电催化作用。在CoPcCN单层修饰玻碳（GC）电极上电沉积的纳米mnox经扫描电镜证实为直径约为10 ~ 20nm的纳米棒。在循环伏安图上，双催化剂修饰的GC电极o2还原峰电流较裸GC电极明显增大，峰电位向正极方向偏移约160mV。Koutecký-Levich图表明，在双催化剂修饰的GC电极上，o2的还原是一个明显的4电子过程。双催化剂修饰GC电极上的收集效率远低于GC电极上的收集效率，与Pt纳米颗粒修饰GC电极上的收集效率基本相似。结果表明，该双催化剂体系对CoPcCN催化氧化还原2电子还原o2为HO2−和纳米mnox催化HO2−歧化为OH−和o2具有双重催化活性，并能在碱性介质中以较低过电位实现o2的4电子还原。此外，还发现双催化剂修饰电极在0.1M硫酸溶液中浸泡清洗后，其对O2还原的催化活性增强。
The electrocatalysis of the dual functional catalysts system composed of electrolytic nano-manganese oxide (nano-MnOx) and cobalt octacyanophthalocyanine (CoPcCN) toward 4-electron reduction of oxygen (O2) in alkaline media was studied. Nano-MnOx electrodeposited on the CoPcCN monolayer-modified glassy carbon (GC) electrode was clarified as the nano-rods with ca. 10–20nm diameter by scanning electron microscopy. The peak current for O2reduction at the dual catalysts-modified GC electrode increases largely and the peak potential shifts by ca. 160mV to the positive direction in cyclic voltammograms compared with those obtained at the bare GC electrode. The Koutecký–Levich plots indicate that the O2reduction at the dual catalysts-modified GC electrode is an apparent 4-electron process. Collection efficiencies obtained at the dual catalysts-modified GC electrode are much lower than those at the GC electrode and are almost similar to those at the Pt nano-particles modified GC electrode. The obtained results demonstrate that the dual catalysts system possesses a bifuctional catalytic activity for redox-mediating 2-electron reduction of O2to HO2−by CoPcCN as well as catalyzing the disproportionation of HO2−to OH−and O2by nano-MnOx, and enables an apparent 4-electron reduction of O2at a relatively low overpotential in alkaline media. In addition, it has been found that the cleaning of the dual catalysts-modified electrode by soaking in 0.1M sulfuric acid solution enhances its catalytic activity toward the reduction of O2.