Hydrogen production with polyaniline/multi‐walled carbon nanotube cathode catalysts in microbial electrolysis cells

BACKGROUND Microbial electrolysis cells ( MECs ) have been considered a promising approach for hydrogen production from renewable biomass. The optimization of the cathode catalyst is important in the study of MECs . Based on the hydrogen production rate (Q) and the chemical oxygen demand ( COD ) removal as the evaluation standards, this research focused on the use of the polyaniline ( PANI )/multi‐walled carbon nanotube ( MWCNT ) composites as the cathode catalysts to replace platinum (Pt) in a single‐chamber membrane‐free MEC . RESULTS Scanning electron microscopy ( SEM ) and linear sweep voltammograms ( LSV ) were used to evaluate the morphology and electrocatalytic activity of the cathodes. At an applied voltage of 1.0 V, the MEC with 75% wt PANI / MWCNTs cathodes achieved a hydrogen production rate of 1.04 m 3  m −3 d −1 at a current density of 163 A m −3 , a coulombic efficiency of 47.2%, a cathodic hydrogen recovery of 56.7%, a COD removal of 88%, and an electrical energy efficiency based on an electricity input of 89%, which was comparable with that of a Pt/C cathode. CONCLUSIONS The PANI / MWCNTs cathodes developed achieved a performance comparable with that of the Pt/C cathode in terms of the hydrogen production rate. The PANI / MWCNTs composites used as cathodic catalysts to replace Pt/C substantially reduced the cost of the MECs . © 2014 Society of Chemical Industry