Nanoporous oxide coating on carbon paper electrodes to enable bio-hydrogen production in microbial electrolysis cells.

To counteract expensive cathodes, a single chamber microbial electrolysis cell (MEC) equipped with nanoporous oxide coating on a carbon paper electrode as a cathode was explored. The performance of the MEC was evaluated based on the chemical oxygen demand (COD) removal efficiency, catalytic activity, and hydrogen production. The obtained results indicated that nanoporous oxide coated carbon electrode with TiO 2 achieved maximum H 2 yield (3.0 mol H 2 mol−1 acetate), followed by ZrO 2 and SiO 2. In contrast, the uncoated carbon electrode achieved lower hydrogen yield (0.08 mol H 2 mol−1 acetate). A maximum COD removal of 82% was achieved from the carbon electrode coated with TiO 2 followed by 80.5% from SiO 2 and 79% from ZrO 2. Additionally, based on linear sweep voltammetry, nanoporous oxide coated electrodes started H 2 evolution at a lower potential than the uncoated electrode, thereby exhibiting a higher catalytic rate. This investigation showed that carbon electrodes with nanoporous coating can be one of the economical (low cost) and potential electrodes to be used as a cathode in the MEC for hydrogen production instead of expensive metallic electrodes. [Display omitted] • Low-cost, high potential cathode electrodes were explored. • Nanoporous oxide coated electrodes exhibited high catalytic activity. • Efficient H 2 production with low applied potential. • H 2 yield was higher for nanoporous coated electrodes than uncoated. [ABSTRACT FROM AUTHOR]