Development of a practical formate/bicarbonate energy system.

Liquid (organic) hydrogen carriers ([18H]-dibenzyltoluene, MeOH, formic acid, etc.) form a toolbox for the storage and transport of green hydrogen, which is crucial for the implementation of renewable energy technologies. Simple organic salts have been scarcely investigated for this purpose, despite many advantages such as low cost and minor toxicity, as well as easy handling. Here, we present a potassium formate/potassium bicarbonate hydrogen storage and release energy system, that is applicable and shows high stability (6 months). Utilizing ppm amounts of the molecularly defined Ru-5 complex, hydrogen release rates of up to 9.3 L h -1 were achieved. The same catalyst system promoted the hydrogenation of KHCO 3 to HCOOK with a TON of 9650. In this way, combined hydrogen storage-release cycles can be performed for 40 times.