Ethylene glycol as an efficient and reversible liquid-organic hydrogen carrier

Hydrogen has long been regarded as an ideal alternative clean energy vector to overcome the drawbacks of fossil technology. However, the direct utilization of hydrogen is a challenge because of the low volumetric energy density of hydrogen gas and potential safety issues. Here we report an efficient and reversible liquid to liquid-organic hydrogen carrier system based on inexpensive, readily available and renewable ethylene glycol. This hydrogen storage system enables the efficient and reversible loading and discharge of hydrogen using a ruthenium pincer complex, with a theoretical hydrogen storage capacity of 6.5 wt%.