Synergistic Effect between Pt and CrO<sub><i>x</i></sub> on Reversible Hydrogenation and Dehydrogenation of Dibenzyltoluene
Nian Lei, Sicong Qiu, Ligang Zhang, Guanwei Zhao, Shihao Wang, Kuo Liu
Abstract
Liquid organic hydrogen carriers are a safe and economic alternative for hydrogen storage and long-distance transport. A new dopant, CrO x, was developed and added to Pt/Al 2 O 3, and the obtained catalysts exhibited higher performance of perhydro dibenzyltoluene (H18-DBT) dehydrogenation with the increasing CrO x amounts until 1 wt %. On the contrary, the performance of dibenzyltoluene (DBT) hydrogenation decreased with the increasing amount of CrO x . The degree of dehydrogenation was dramatically improved to 87.2% after adding 1 wt % CrO x compared to the unmodified Pt/Al 2 O 3 catalyst (65.6%), and the hydrogenation activity was stable within ten cycles of reversible hydrogenation and dehydrogenation of DBT. With the increasing CrO x amounts, CrO x species aggregated to polychromates and then crystalline Cr 2 O 3, leading to higher Pt electron density, smaller Pt particle size, and further, a higher dehydrogenation activity and lower hydrogenation performance. Polychromates were identified as important species for dehydrogenation.