Li Liu et al. have conducted a study entitled \u201cSynergistic La\u2082O\u2083-La(OH)\u2083 Interface Engineering Enables Deep and Durable Dehydrogenation of 12H-N-Propylcarbazole over Pd\/Al\u2082O\u2083 Catalysts\u201d. This study was published in Frontiers of Chemical Science and Engineering, Volume 19, Issue 9, 2025.<\/p>\n
Hydrogen, as a highly efficient, clean, and zero-carbon energy carrier, plays a crucial role in the global energy transition. However, challenges in its storage and transportation significantly limit its widespread application. Liquid organic hydrogen carriers (LOHCs) represent a breakthrough technology for hydrogen storage and delivery, among which 12H-N-propylcarbazole (12H-NPCZ) has attracted attention due to its high hydrogen storage capacity and moderate dehydrogenation conditions. Palladium (Pd) is the metal of choice for catalyzing the dehydrogenation of such compounds, and alumina (Al\u2082O\u2083) is commonly used as a support. Nevertheless, issues such as Pd nanoparticle agglomeration, insufficient catalytic activity, and poor stability need to be addressed, while lanthanum (La)-based promoters show potential in optimizing catalyst performance.The researchers prepared a series of alumina composite supports with varying La contents via a co-precipitation\/hydrothermal route, and deposited Pd nanoparticles to obtain Pd\/La\u2093AlO catalysts. Comprehensive characterization and 12H-NPCZ dehydrogenation performance tests were carried out. The results showed that an optimal 10 wt% La loading led to the formation of intimately interfaced La\u2082O\u2083 and La(OH)\u2083 nanodomains on the support surface, which anchored highly dispersed Pd particles (~2.2 nm), donated electrons to Pd\u2070, and constructed bifunctional acid-base sites along with a fast hydrogen-spillover network. The Pd\/La\u2081\u2080AlO catalyst achieved the theoretical H\u2082 release (5.43 wt%) within 150 minutes at 180 \u00b0C, with 99% NPCZ selectivity and no activity loss over ten cycles. Kinetic analysis revealed that La doping significantly reduced the apparent activation energies of the three successive dehydrogenation steps, with a ~65 kJ\u00b7mo-1drop in the rate-limiting 4H-NPCZ\u2192NPCZ stage.This study provides the first mechanistic evidence that the coexistence of La\u2082O\u2083 and La(OH)\u2083 can cooperatively tune the electronic and interfacial structure of Pd\/Al\u2082O\u2083, offering clear guidelines for designing efficient and stable dehydrogenation catalysts for N-heterocyclic LOHCs.<\/p>\n