Electrochemical tuning of the activity and structure of a copper-cobalt micro-nano film on a gold electrode, and its application to the determination of glucose and of Chemical Oxygen Demand

Jinqi Wang; Na Yao; Mei Li; Jia Hu; Jianwei Chen; Qiaoling Hao; Kangbing Wu; Yikai Zhou

doi:10.1007/s00604-014-1353-z

Electrochemical tuning of the activity and structure of a copper-cobalt micro-nano film on a gold electrode, and its application to the determination of glucose and of Chemical Oxygen Demand

Mikrochim Acta. 2015;182(3):515-522. doi: 10.1007/s00604-014-1353-z. Epub 2014 Sep 17.

Authors

Jinqi Wang¹, Na Yao¹, Mei Li¹, Jia Hu¹, Jianwei Chen¹, Qiaoling Hao¹, Kangbing Wu², Yikai Zhou¹

Affiliations

¹ MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China.
² MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China ; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074 China.

Abstract

Micro-nano structured Cu-Co was in situ fabricated on the surface of a gold electrode via electrochemical reduction of CuCl₂ and Co(NO₃)₂. It is shown that the shape of the particles can be controlled by variation of deposition current, deposition time, pH value and the ratio of Cu(II) and Co(II) ions. If prepared under current of -200 μA in 0.1 M, pH 4.0 acetate buffer solution, the film possesses high catalytic activity towards the electrochemical oxidation of glucose at a largely increased oxidation current compared to a non-modified surface. The electrochemical activity of this sensor can be easily tuned. Glucose is a standard compound for evaluating the chemical oxygen demand (COD), and we have therefore studied the application of the sensor to the determination of this parameter. Under optimized conditions, the sensor has linear response to glucose in the 1.92-768 mg L^-1 concentration range, and the detection limit is 0.609 mg L^-1 (at an S/N ratio of 3). A large number of surface water samples was studied, and the results obtained by this method were found to be linearly correlated to those obtained by the dichromate method (r = 0.995; n = 33). Graphical AbstractThis study describes the facile synthesis of micro-nano Cu-Co by one-step electrodeposition of Cu(II) and Co(II) on gold electrode. The alloy composite exhibited excellent electrocatalytic activities, and was successfully applied on the COD determination of glucose and water samples.

Keywords: Chemical oxygen demand (COD); Electro deposition; Electrochemical sensor; Gold electrode; Micro-nano Cu-Co.