Macromolecular Synthesis by Air Oxidative Polymerization through Multi-electron Transfer

多电子转移空气氧化聚合高分子合成

基本信息

批准号：
12650870
负责人：
YAMAMOTO Kimihisa
金额：
$ 2.37万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Research of the four-electron reduction of oxygen to water is important in order not only to determine the life mechanism but also to make novel catalysts.As face-to-face Cobalt Dinuclear Porphyrins (CoP2) are known as excellent catalysts to promote the reaction. Polymer complexes of CoP2 with Polyaniline were prepared on the electrode as a catalyst. Electrochemical properties of Polyaniline-CoP2 complex was investigated and proved to catalyze 4-electron reduction by 80%, compared to 50% by CoP2 modified electrode. In order to establish essential factor to promote catalytic efficiency of CoP2, various conducting polymers including self-dope polyaniline, and proton transfer redox polymer were synthesized. It probed that the efficiency of 4-electron reduction is strongly dependent on the redox potential of the polymer-matrix, indicating that redox potential of polymer is an important factor in this catalytic system. As PCAn acts as an efficient electron mediator even in neutral conditions due to its stable redox activity over wide pH range, catalytic reduction of oxygen was carried out using PCAn-CoP2 complex in neutral conditions (pH=6.2). A catalytic efficiency up to 95% toward 4-electron reduction of oxygen was observed by RDV, and RRDV measurements. One-step 4-electron reduction was occurred, not two steps 2-electron transfer by RRDV. It is because PCAn has acidic domain in the polymer matrix, which is thought to keep acidity in the film to some extent, even in neutral conditions, that 4-electron reduction of oxygen occurs in the neutral conditions.

氧四电子还原成水的研究不仅对于确定其寿命机制而且对于制造新型催化剂具有重要意义。面对面的钴双核卟啉（CoP2）被称为促进该反应的优异催化剂。在电极上制备了 CoP2 与聚苯胺的聚合物复合物作为催化剂。研究了聚苯胺-CoP2 复合物的电化学性能，结果证明其催化 4 电子还原能力提高了 80%，而 CoP2 修饰电极的催化能力为 50%。为了确定提高CoP2催化效率的关键因素，合成了包括自掺杂聚苯胺和质子转移氧化还原聚合物在内的各种导电聚合物。研究发现，4 电子还原效率强烈依赖于聚合物基体的氧化还原电位，表明聚合物的氧化还原电位是该催化体系中的重要因素。由于 PCAn 在较宽的 pH 范围内具有稳定的氧化还原活性，即使在中性条件下也可充当有效的电子介体，因此在中性条件下（pH=6.2）使用 PCAn-CoP2 复合物进行氧的催化还原。通过 RDV 和 RRDV 测量观察到氧的 4 电子还原催化效率高达 95%。 RRDV 发生一步 4 电子还原，而不是两步 2 电子转移。这是因为PCAn在聚合物基体中具有酸性区域，这被认为即使在中性条件下也能在一定程度上保持薄膜的酸性，所以在中性条件下会发生氧的4电子还原。