Qingqing Li,Zhiwei Sun,Yilin Wei,Zixu Ma,Liucheng Wang,Renfeng Nie
Reversible hydrogen storage via Liquid organic hydrogen carriers (LOHCs) is one of the key technologies for efficient utilization of hydrogen energy. How to construct efficient dehydrogenation/hydrogenation catalysts that enable low-temperature catalysis still remains challenging. Herein, we present the design and construction of single-atom Co-N-C(x) catalysts allowing significantly improved acceptorless dehydrogenation of 1,2,3,4-tetrahydroquinoline (THQ). By varying the ligand/Co ratio, the optimal Co-N-C(1.5) can achieve 97.5% dehydrogenated product and 0.82 h −1 TOF value at ambient temperature, overperforming many reported non-noble metal even noble metal catalysts. This catalyst exhibits good recyclability and substrate versatility, enabling ambient temperature dehydrogenation of various N-heterocycles and efficient reverse hydrogenation of aromatic N-heterocycles, thus achieving the loop of reversible hydrogen storage. The active catalyst centers consist of specific Co-N x moieties and nitrogen species within the carbon support. Controlled experiments reveal that the different performance of Co-N-C(x) is determined by density of the Co-N x , and the rate-determining step of THQ dehydrogenation is correlated with the bond cleavages in surface-bound THQ. This work offers a promising pathway for energy-efficient and cost-effective hydrogen energy utilization under practical conditions.
Novel porous hollow carbon nanospheres (HCNS) have been synthesized and utilized as scaffold for LiBH 4 –Mg(BH 4 ) 2 eutectic borohydride (LMBH). Large loading amounts of LMBH (33, 50 and 67 wt%) have been melt-infiltrated into HCNS, and the significantly improved dehydrogenation properties have been discovered. The LMBH@HCNS composites not only exhibit high actual dehydrogenation amounts and fast hydrogen desorption rates, but also an increased reversible hydrogen storage capacities after three cycles without obvious degradation. Further structural tests have revealed that the over-infiltrated LMBH covering the spherical surface of HCNS could also contribute to the improved hydrogen storage behaviors, due to a strong interfacial adhesion effect that avoid LMBH from aggregation during de/rehydrogenation cycles.
危险品化学品经营许可证（带存储）