Enhancing biohydrogen production from sugar industry wastewater using metal oxide/graphene nanocomposite catalysts in microbial electrolysis cell

Biohydrogen production through Microbial Electrolysis Cell (MEC) has drifted towards the development of suitable cost-effective cathode catalysts. In this study, two graphene hybrid metal oxide nanocomposites were used as catalysts to investigate hydrogen production in the MEC operated with sugar industry wastewater as substrate against phosphate buffer catholyte. Electrochemical characterizations exposed the better performance of NiO(center dot)rGO coated cathode which showed lesser overpotential at 600 mV and overall lowest resistance in the Nyquist plots than Ni-foam and Co(3)O(4 center dot)rGO cathodes. The experimental results showed that at an applied voltage 1.0 V, NiO(center dot)rGO nanocomposite had exhibited maximum hydrogen production rate of 4.38 +/- 0.11 mmol/L/D, Coloumbic efficiency of 65.6% and Cathodic hydrogen recovery of 20.8% respectively. The MEC performance in terms of biohydrogen production was 1.19 and 2.68 times higher than Co(3)O(4 center dot)rGO and uncoated Ni-Foam. Hence, economical hybrid nanocomposite catalysts were demonstrated in MEC using industrial effluent for energy and environment sustainability. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.