"BioNanoCat" - Biogenic Nanoparticles Prepared from Bacterial Biofilms for Electrocatalytic and Fuel Cell Device Applications

Fuel cells are devices which exploit redox processes as power sources. State-of-the-art H2/O2 fuel cells employ precious metal catalysts such as Pt and other Pt-group metals, presenting issues of cost and sustainability. There is therefore a significant interest in exploring nonprecious transition metals (e.g. Fe, Co, Mn) as catalysts in particular for the oxygen reduction reaction (ORR), the current ‘bottle-neck’ in improved fuel cell catalyst performance. Certain bacterial cultures are known to form biofilms with a high tolerance to these aforementioned metals through evolved mechanisms for neutralising the toxic effects of heavy metal ions, such as membrane complex formation and intracellular precipitation of the metal ions as nanoparticles. In this project, I aim to exploit this natural metal tolerance to employ bacterial biofilms as living factories for the preparation of biogenic non-Pt metal electrocatalysts. I will prepare biofilm-modified carbon electrodes by immersing surface-modified carbon electrode materials in solutions containing controlled amounts of chosen metal ions (e.g. Mn, Co and other heavy metals with potential electrocatalytic activity). After optimising the metal sequestering properties of these biofilms, I will subject the resulting modified electrodes to thermal annealing treatments to form high-activity carbon-supported transition metal electrocatalysts and evaluate their performance as novel, biologically-derived catalysts for ORR