Aqueous Formiate-Bicarbonate for Hydrogen Storage

Hydrogen is recognized as a crucial energy vector the next-future circular economy. Investigate new processes for sustainable hydrogen storage is fundamental to enable fast and capillary diffusion of H2 technologies. However, at present, mature H2 storage technologies, i.e. high-pressure and/or cryogenic liquid H2, still present many limitations and safety issues, also affecting public perception and acceptance of H2-powered devices. H2 release and uptake through cyclic interconversion of formate/bicarbonate aqueous solutions (Figure) at near-ambient conditions is an intrinsically safe and easy-to-handle storage system. Preliminary energetic assessment suggest that the available catalysts could meet the requirements for mobile applications in the automotive sector with storage tanks in the range of 200 L, with an energetic efficiency of about 72%, improvable up to 90%, depending on reaction temperature and pressure. From a thermodynamic point of view the reaction can be easily shifted at near ambient conditions (T = 20-90 °C; P = 1-30 atm) by slightly changing the operating conditions.