K-promoted Pt/meso-Al2O3 catalysts for H2 production from dehydrogenation of dodecahydro‑N‑ethylcarbazole

N -ethylcarbazole, as a liquid organic hydrogen carrier, has shown great promise in the field of hydrogen storage technology. The development of efficient and stable catalyst for producing H 2 through N -ethylcarbazole dehydrogenation is crucial for its practical application. In this study, a series of mesoporous Al 2 O 3 -supported Pt catalysts with K modification were developed for N -ethylcarbazole dehydrogenation. These catalysts were characterization using various techniques including XRD, N 2 adsorption–desorption, TEM, 27 Al MAS NMR, XPS, NH 3 -TPD, H 2 -TPR, CO-FTIR, and Py-IR, providing detailed structural information to elucidate the structure–activity relationship. Mesoporous Al 2 O 3 was found to possess significant amounts of coordinatively unsaturated pentacoordinate Al 3+ , which greatly promotes the dispersion of Pt species for the formation of small Pt particles. The addition of K was observed to modulate the electronic structure of Pt, reduce the acidity of the catalysts, and inhibit the sintering of Pt. These synergetic effects led to Pt 3.0 /K 3.0 -Al 2 O 3 -m achieving remarkable performance in dodecahydro- N -ethylcarbazole dehydrogenation at 180 °C and 101 kPa, delivering a dodecahydro- N -ethylcarbazole conversion of 100 %, H 2 release amount of 5.63 wt% and dehydrogenation efficiency of 97.10 %. Additionally, this catalyst demonstrated high efficiency in the dehydrogenation of dodecahydro- N -propylcarbazole, octahydro-2-methylindole, and octahydro-1,2-dimethylindole, achieving dehydrogenation efficiencies of 99.60 %, 100 % and 100 %, respectively. These findings provide valuable knowledge for the rational design of efficient metal-based catalysts for liquid organic hydrogen carriers in hydrogen storage systems.