Iridium(I)NHC-phosphine complex-catalyzed hydrogen generation and storage in aqueous formate/bicarbonate solutions using a flow reactor - Effective response to changes in hydrogen demand

Hydrogen gas generation with an effective response to changing application demands was achieved with the use of a hydrogen storage battery based on aqueous cesium bicarbonate hydrogenation/formate dehydrogenation, homogeneously catalyzed by an Ir(I)N-heterocyclic carbene complex. In this device, the storage solution was circulated through a small volume tubular reactor heated to the required high temperature to allow fast hydrogen evolution while the high volume reservoir was kept at ambient temperature at which no H₂ was generated. Merely by the control of the reactor temperature, it was possible to regulate the rate of hydrogen evolution as required. The results also demonstrate the feasibility of homogeneous catalysis for the purpose of hydrogen generation in flow systems.