Formic Acid-powered Ferrobots For Clean Energy Technology
Amit Kumar Singh, Saptak Rarotra, Viswanath Pasumarthi, Tapas Kumar Mandal, Dipankar Bandyopadhyay
Centre for Nanotechnology, Indian Institute of Technology Guwahati, Assam -781039
Abstract: Hydrogen fuel cells work by instigating stored hydrogen to react with oxygen in the air, producing electricity and water. However, the generation of pure hydrogen fuel can be a challenging problem. The large-scale production of the hydrogen gas is mostly achieved by steam-methane reforming process. The major drawback of the steam reforming is that – (i) it takes place at high temperature and thus requires external heat energy to maintain the elevated temperature and (ii) the process results in the emission of greenhouse gases as a by-product of the reaction. Furthermore, hydrogen storage and transportation are expensive and requires exclusive tanks to store the gas at enormously high pressure. To address this issue, we report self-propelling Ferrobots composed of a collection of iron nanoparticles (FeNPs), for rapid on-site generation of pure hydrogen gas using formic acid as fuel. Instead of storing hydrogen gas in bulky pressurized tanks, the motile Ferrobots could be easily deployed into aqueous formic acid solutions for on-demand release of the pure hydrogen gas, devoid any of greenhouse gases, at room temperature. To demonstrate the proof-of-concept, the reactive Ferrobots were employed to power a portable toy fan equipped with a PEM fuel cell. The pure hydrogen gas required for the PEM fuel cell was generated through the reaction of the formic acid solution with self-propelling Ferrobots, whereas, the oxygen gas was produced by catalytic decomposition of peroxide fuel using the same Ferrobots. The as-generated hydrogen and oxygen gases directly fed from the reaction chambers to the fuel cell electrodes to generate electricity and thus power the electronic toy fan. The advantage of this type of micromotor-mediated system is that liquid fuels are used for on-site hydrogen release, and therefore gas storage will not be prerequisite in the near future.