In situ preparation of Pd nanoparticles on N-doped graphitized carbon derived from ZIF-67 by nitrogen glow-discharge plasma for the catalytic dehydrogenation of dodecahydro-N-ethylcarbazole

To date, liquid organic hydrogen carrier technology has been generally considered to be one of the most promising solutions for the storage and transportation of hydrogen. Addressing several issues, including high hydrogen release temperature and low initial release rate, is key to this technology. Pd catalysts (Pd/NpGC) supported on porous N-doped partially graphitized ZIF-67-derived carbon (NpGC) were prepared in situ using nitrogen glow discharge plasma. The structure, composition, and morphology of the prepared catalysts were characterized by XRD, Raman spectroscopy, TEM, XPS, and N2 adsorption-desorption. During the calcination of ZIF-67, porous N-doped carbon was formed and partially graphitized under the influence of Co. The Pd nanoparticles (Pd NPs) of the Pd/NpGC catalysts had an average size of 3.2 nm with higher dispersion and a higher fraction of Pd (111) facets. In the process of Pd2+ reduction, NpGC was doped twice with N simultaneously. The synergy between highly active Pd NPs and N-doped partially graphitized carriers (NpGC) reduced the electronic binding energy of Pd and improved the catalytic performance of Pd/NpGC for hydrogen production from dodecahydro-N-ethylcarbazole (H12-NEC). The results showed that the amount of hydrogen released in the dehydrogenation reaction at 180celcius was 4.06 wt% after 1 h and 5.76 wt%, after 10 h. The H12-NEC conversion rate was 100%, the selectivity of N-ethylcarbazole (NEC) was 98.72%, and the final dehydrogenation reached 99.20%.