Synergistic Strategy for the Fast Dehydrogenation of Liquid Organic Hydrogen Carriers over a Pd/MoO3 Catalyst

We report a synergistic strategy for the dehydrogenation of liquid organic hydrogen carriers (LOHCs) over a Pd/ MoO3 catalyst. The effects of Pd loading, temperature, and the variation of HxMoO3 for the catalytic dehydrogenation behavior of LOHCs were investigated systematically. 5 wt % Pd/MoO3 shows the highest catalytic performance. 3.13 wt % release of the stored H-2 of perhydro-N-ethylcarbazole (PNEC) was achieved in the initial 5 min, and full dehydrogenation was realized in 1.5 h at 200 ?. The kinetic results suggest that the turn-over frequency (TOF) of PNEC on the 5 wt % Pd/MoO3 catalyst is 191.11 min(-1) at 180 ?, which is significantly larger than that of traditional noble metal catalyst 5 wt % Pd/Al2O3 (56.31 min(-1)). The dehydrogenation mechanism on Pd/MoO3 essentially differs from the traditional noble metal catalysts. The formation of HxMoO3 other than H-2 greatly decreases the activation energy barrier of the dehydrogenation reaction and results in the swift desorption of H atoms from PNEC. The results indicate that the synergistic effect between Pd and MoO3 may be an efficient strategy for the fast dehydrogenation of LOHCs.