Layer-by-layer assembled gold nanoparticles modified anode and its application in microbial fuel cells

Microbial fuel cells (MFCs) as one type of “green” energy source are drawing great attention among researchers. Anode performance is an important factor limiting the power output of MFCs for practical application. In this paper, the gold nanoparticles (Au NPs) modified carbon paper electrode was successfully constructed by layer-by-layer assembly technique for the first time. UV–vis spectroscopy was used to monitor the regular layer growth of the {PEI/Au}10 multilayer. The results of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in Fe(CN)63−/4− solution demonstrated that the Au NPs modified carbon paper electrode exhibited better electrochemical behavior than the bare carbon paper electrode, including relatively high electroactive surface areas, increased electron transfer rate and decreased interfacial electron transfer resistance. A two-chambered MFC equipped with the modified anode achieved a maximum power density of 346 mW m−2 and a start-time for the initial maximum stable voltage of 175 h, which were respectively 50% higher and 36% shorter than the corresponding values of the MFC with the unmodified anode. All the results indicated that the LBL assembly Au NPs-based modification on the anode was a simple but efficient method to incorporate Au NPs onto carbon paper electrodes and promoted the electricity generation of MFCs.