摘要
采用循环伏安法、微分脉冲伏安法、交流阻抗谱以及计时电流法等电化学方法,结合红外光谱、紫外-可见分光光度法、原子力显微镜、透射电子显微镜以及原子吸收光谱等辅助手段,表征了固定漆酶的聚苯胺-草酸钴纳米复合物的化学组成、结构和形貌,测试了纳米复合物固酶前后的导电性能的变化,研究了纳米复合物修饰电极上固定漆酶的直接电化学行为,评估了该电极的催化氧还原效能以及作为电化学传感器检测氧分子的性能。实验结果表明该电极在不含电子介体的溶液中以酶活性中心T2作为首要电子受体,将得到电子传递给化学吸附的氧气使其被电还原,其表观电子迁移速率为0.017 s^(-1),且具有良好的催化氧还原性能(氧还原起始电位:460 m V vs NHE,转化氧分子为水的表观速率常数为2.6×10-4 s^(-1)),酶电催化氧还原为水分子步骤为反应的速控步。该电极作为电化学传感器对氧具有极低检测限(0.20μmol·L^(-1)),宽线性响应范围(0.4~7.5μmol·L^(-1))以及对底物高亲和力(KM=122.4μmol·L^(-1))等优势。
Electrochemical methods including cyclic vohammetry, differential pulse vohammetry, electrochemical impedance spectrometry and ehronoamperometry, together with auxiliary means such as F-T infrared spectrometry, Ultra-violet visible spectrometry, atomic force microscopy, transmission electron microscopy and atomic adsorption spectrometry were used to characterize the chemical composition, structure and morphology of polyaniline-CoC2O4 nano-composite, to measure the change of conductivity in nano-eomposite before and after Laccase immobilization and to investigate the direct electrochemistry of redox protein molecules entrapped in the matrix. Its catalytic effect on oxygen reduction reaction and performance as electrochemical sensor for oxygen detection were evaluated subsequently. Results from tests indicated this Laccase-based electrode shuttled electrons from enzyme active site T2 as primary electron acceptor to dioxygen molecules attached chemically in the matrix, achieving the electro-reduction of O2 in the absence of any external mediator with its apparent electron transferring rate： 0.017 s-1. This laeease-based electrode displayed favorable catalytic effect on oxygen reduction reaction （onset potential for catalysis： 460 mV vs NHE, apparent turn-over frequency for oxygen reduction reaction： 2.6 ×10^-4 s^-1）.Enzymatic oxygen electro-reduction into water should be ascribed to the key process to promote the performance of biocathode. This Laccase based electrochemical sensor had such advantages as extremely low detection limit （0.20 μmol. L-1） to oxygen monitoring, wide linear responding range of concentration （0.4-7.5 μmol. L-1） and high affinity towards substrate （KM=122.4 μ mol.L-1）.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2016年第12期2117-2128,共12页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.21363024,31560249)
新疆师范大学博士科研启动基金(No.XJNUBS1228)
新疆师范大学研究生科技创新项目基金(No.XSY201502009)
新疆师范大学大学生创新创业项目(No.201510762074)资助
新疆维吾尔自治区2013年度高校科研计划青年教师培育项目(No.XJEDU2013S29)
关键词
聚苯胺-草酸钴纳米复合物
漆酶
直接电化学
催化氧还原反应
电化学传感器
Polyaniline-CoC2O4 nano-composite
Laccase
Direct electrochemistry
Catalytic oxygen reduction reaction
Electrochemical sensor
