Pyrolysis of Corncobs to Produce Biobased Conductive Materials as Electrodes for Potential Application in Microbial Fuel Cells (MFCs)

Abstract

Despite large varieties of commercially available electrodes, only few are suitable for electro-active bacterial colonization during biofilm formation in microbial fuel cells (MFCs), and most of these electrodes are cost prohibitive. Hence there is need to search for low-cost alternative electrodes for MFCs. Pyrochars were produced in this study by pyrolysis (600 °C and a continuous flow rate of 3 L/min of nitrogen gas for 30 min) and subsequently steam and potassium hydroxide (KOH) activation of the pyrochar at 600 °C were carried out accordingly. Physicochemical, structural, and electrochemical properties of the activated and non-activated pyrochars were determined according to standardized analytical methods. According to BET, 1626 m2 g-1 surface area and 14.74 Å pore diameter were obtained from the KOH-activated pyrochar which was also the most conductive (0.26 S m-1). Chemical activation of pyrochar with KOH resulted in increased electrical conductivity (EC), pore diameter, and most importantly the material’s surface area according to the findings. In conclusion, KOH-activated corncob pyrochar holds potentials for producing electrode materials with desirable characteristics for successful application in MFC compared to the non-activated and steam-activated pyrochars of the same biomass.