2-(N-Methylbenzyl)pyridine: A Potential Liquid Organic Hydrogen Carrier with Fast H₂ Release and Stable Activity in Consecutive Cycles

The liquid organic hydrogen carrier (LOHC) 2-(N-methylbenzyl)pyridine (MBP) shows good potential for H₂ storage based on reversible hydrogenation and dehydrogenation, with an H₂ storage density of 6.15 wt %. This material and the corresponding perhydro product (H₁₂-MBP) are liquids at room temperature. Remarkably, H₂ release is much faster from H₁₂-MBP over Pd/C than from the benchmark perhydro benzyltoluene over Pt/C at lower temperatures than 270 °C, owing to the addition of N atom into the benzene ring. Since this positive effect is unfavorable to the hydrogenation reaction, more Ru/Al₂O₃ catalyst or prolonged reaction time must be applied for complete H₂ storage. Experiments with repeated hydrogenation–dehydrogenation cycles reveal that reversible H₂ storage and release are possible without degradation of the MBP/H₁₂-MBP pair. The prepared MBP satisfies the requirements for chemical stability, handling properties, and cytotoxicity testing.