Osmium Complex Grafted on a Carbon Electrode Surface as a Mediator for a Bioelectrocatalytic Reaction
摘要:
提出了一种用氧化还原活性胺对碳电极进行电化学修饰的新方法,用于介导酶与电极之间的电子转移。以组胺配位的 Os 复合物作为氧化还原胺模型进行了合成。该复合物的电氧化作用在氨基的氮原子和电极表面的碳原子之间产生了稳定的共价连接。共价连接的 Os 复合物在电极上显示出良好的氧化还原反应,作为电极与模型酶(依赖 PQQ 的水溶性葡萄糖脱氢酶)之间的电子转移介质,具有很高的活性。
A Laccase-Wiring Redox Hydrogel for Efficient Catalysis of O<sub>2</sub> Electroreduction
作者:Nicolas Mano、Valentine Soukharev、Adam Heller
DOI:10.1021/jp055654e
日期:2006.6.1
Laccase was earlier wired to yield an O-2 electroreduction catalyst greatly outperforming platinum and its alloys. Here we describe the design, synthesis optimization of the composition, and characterization of the +0.55 V (AgAgCl) laccase-wiring redox hydrogel, with an apparent electron diffusion coefficient (D-app) of 7.6x10(-7) cm(2) s(-1). The high D-app results in the tethering of redox centers to the polymer backbone through eight-atom-long spacer arms, which facilitate collisional electron transfer between proximal redox centers. The O-2 flux-limited, true-area-based current density was increased from the earlier reported 560 to 860 mu A cm(-2). When the O-2 diffusion to the 7-mu m-diameter carbon fiber cathode was cylindrical, half of the O-2 flux-limited current was reached already at 0.62 V and 90% at 0.56 V vs Ag/AgCl, merely -0.08 and -0.14 V versus the 0.7 V (Ag/AgCl) reversible O-2/H2O half-cell potential at pH 5.