Electrochemical Characteristics of Gold Microarray Electrode and Its Application in Microbial Fuel Cells

Author:Chen Shan

Supervisor:tian yang chao liu gang


Degree Year:2019





As a kind of new fuel cell technology,microbial fuel cells(MFCs)can restore electricity during the degradation of pollutants,which gradually has aroused wide attention of scientific research workers in the past ten years.Electrode is the important component section of MFCs,and its property could directly influence on the performance of MFCs and wastewater treatment efficiency.In order to improve the adhesion and electron transfer between electrochemically active bacteria(EAB)and electrode surface,scientific research workers have made extensive and profound studies on the material and structure of electrodes in MFCs.Gold microarray electrode is composed by many gold microelectrode in parallel prepared by ultra-violet lithography technology.And it could not only keep the excellent electrochemical characteristics of single microelectrode,which including very high steady state current density,very short response time,high rate of mass transfer,high signal-to-noise ratios,low IR drop,low polarization current and et al,but also amplify the detection signals by parallel gold microelectrode.What is more,gold microarray electrode also could achieve the manipulation of microorganism by designing special electrode structure,controlling the liquid flow velocity,adding the external electric field and et al,which makes it become a very effective research tool in the field of electrochemistry and biology.In this study,it was the first attempt to apply gold microarray electrode into the study of MFCs,and carry out a detailed study on the influence of improving electricity production performance by gold microarray electrode.Scientific foundation could be provided for applying gold microarray electrode into the study of meso-and micro-MFCs in the future.So far,classical Derjaguin-Landau-Verwey-Overbeek(DLVO)theory is relatively perfect theory to explain colloid stability.And based on this theory,extended-DLVO theory has developed to explain the adsorption phenomena between bacteria and solid surface by introducing Lewis acid-base forces,which is the most comprehensive analysis of the free energy of short term interactions between bacteria and a substrate.In this study,it had been done to make an analysis and prediction of the adhesion between EAB and the surface of gold microarray electrode,and it successfully explain the reason why EAB formed diverse biofilm on different substrate which was as a support layer of gold microarray electrode.It also provides the theory support in the application of MFCs using gold microarray electrode.Gold microarray electrode on substrate of polymethyl methacrylate(PMMA)made EAB form loose and instability biofilm on it because of its high repulsion barrier,on the contrary,EAB form dense and stability biofilm on gold microarray electrode on substrate of glass because EAB could overcome the low repulsion barrier.Gold microarray electrode usually needs substrate as support layer during micromachining process,and different substrate could impact electrochemical response of gold microarray electrode.In this study,potassium ferricyanide solution was used to investigate electrochemical catalytic activity of gold microarray electrode,it was discovered that gold microarray electrode on PMMA and glass showed similar electrochemical catalytic activity,better than gold plate electrode with the same surface area.Then riboflavin,a kind of redox mediator secreted by EAB during the process of the electrons transfer,was treated as studied object.The electrochemical response of riboflavin on the surface of gold microarray electrode was investigated by cyclic voltammetry,and the influence of different substrate during the process of electrochemical response was discussed.We found that gold microarray electrode on substrate of PMMA and glass were controlled by the process of adsorption and diffusion respectively.It means that different substrate materials could influence the electrochemical response of riboflavin on the surface of gold microarray electrode.Based on the theoretical and experimental result of all above,it was investigated that the electricity production performance of MFCs using gold microarray electrode as anode.Compared with other conventional meso-MFCs,the MFCs in this study had the advantages of short start-up time and quick recovery,especially using gold microarray electrode on substrate of PMMA.This result was related with the adsorption of riboflavin on PMMA and the loose and instability EAB biofilm.According to above theoretical analyses and experimental study,as the conclusions,we think gold microarray electrode is a kind of suitable electrode material and structure to study MFCs by reason of its admirable electrochemical characteristics and varied structure.It was helpful to improve the performance of MFCs by deeply understand of EAB adhesion on the surface and its electron transfer mechanism.