Pulse-Opencircuit Voltammetry: A Novel Method Accurately Measuring Bioanode Performance from Microbe-Electrode Interfacial Processes

Abstract

Bioanode which generates current through microbe-electrode interfacial processes (MEIPs) is key to implement various environmental applications of bioelectrochemical systems. However, survey of the contributions of MEIPs to bioanode performance lacks efficient methods. For this aim, we propose a novel pulse-opencircuit voltammetry (POV) based on the analytical principle clarified from the electron flow pathways of MEIPs. Meanwhile, a dual-cathode cell is designed to provide a universal experimental platform for ensuring precise data acquisition of bioanodes. This POV method enables to measure steady state polarization curves and ohmic potential loss curves by integrating potentiostatic discharge and current interruption techniques. Especially, the biofilm reaction resistance (R B,act ) and biofilm ohmic resistance (R B,ohm ) can be determined through the assistance of impedance spectroscopy measuring material resistance. The analysis results of various bioanodes demonstrate that R B,act is the principal limiting factor of bioanodes and its value relies on catabolism state. Whilst R B,ohm is a useful index of electroactive biofilm evolution due to its relevance to extracellular electron transfer behaviors. We anticipate that this method together with the cell platform aiming at accurate and facile bioelectrochemical analysis has wide applications in bioanode construction and electroactive bacteria investigation.

Keywords: bioelectrochemistry, pulse-opencircuit voltammetry, microbe-electrode interfacial processes, resistance distribution, polarization curve