No abstract

Liquid organic hydrogen carrier (LOHC) has attracted a great deal of attention in recent years for its use in hydrogen storage. Supported Rh catalyst has been widely used in the hydrogenation reaction of the N-ethylcarbazole (NEC), one of the most promising LOHCs. However, the high Rh content is challenging because of its high cost. Herein, we successfully developed a γ-Al 2 O 3 -supported Rh-Ni bimetallic catalyst with only 0.1 wt % Rh, which showed excellent catalytic performance in the hydrogenation of NEC with a high conversion of 99% and high selectivity of 98% in 2 h. Various characterizations such as highangle annual dark-field scanning transmission electron microscopy images with phase mappings, X-ray photoelectron spectroscopy, H 2 temperature-programmed desorption, and in situ diffuse reflectance infrared Fourier transform spectroscopy confirmed that the excellent catalytic performance was ascribed to the following factors: (i) electron transfer between the bimetallic Rh-Ni nanoparticles (NPs) structure on the catalyst support; (ii) formation of smaller Ni NPs on the bimetallic Rh-Ni catalyst, which was promoted by Rh; (iii) increased reducibility of the loaded NiO during the catalyst preparation process as a result of the highly dispersed single Rh atom. Thus, the prepared catalyst with ultralow Rh content in this work still has outstanding catalytic activity and sheds light on a fruitful strategy for developing low-cost hydrogenation catalysts of NEC for hydrogen storage.

Well crystallized hollow fibers assembled by c‐axis oriented ZSM‐5 crystals were successfully synthesized via a facile one‐pot solvent‐free route, using quartz fiber as silicon substrate and NH4HCO3 as the growing inhibitor on the crystal faces. The immigration of silica inside the quartz fibers formed the hollow morphology and the shell of hollow fiber was composed by the ZSM‐5 crystals. In addition, the length of c‐axis of ZSM‐5 could be controlled by the amount of NH4HCO3, which selectively inhibited the growth on (010) surface. The obtained ZSM‐5 hollow fibers gave a hierarchical structures composed by micro‐, meso‐ and macropores. Catalytic tests for methanol to gasoline (MTG) revealed that the resultant ZSM‐5 hollow fiber exhibited excellent performance with higher C5+ selectivity and longer lifetime due to the improved mass transfer inside the unique hollow fiber structure.