Pyridine N-induced intra-pore and interfacial dual-confined Pd0-Pdδ+ synergistic catalysis for ultra-stable dehydrogenation of dodecahydro-N-propylcarbazole

Abstract

We developed nano Pd catalysts, encapsulated within carbon-nitrogen layers at both intra-pore and interfacial levels on SiO2, via in-situ thermolysis of metal-organic coordination compounds. The catalysts dehydrogenation efficacy is greatly influenced by thermolysis temperature and ligand-to-metal ratio. The Pd-C-N2/SiO2-600 catalyst notably achieved complete dehydrogenation of 12 H-NPCZ within 240 minutes, demonstrating exceptional stability over 10 cycles without significant degradation, highlighting its viability for commercial use. Characterizations revealed that the C-N layer integration improves Pd nanoparticle dispersion and reduces strong acid site formation on catalyst surface. This synergy between the C-N layer and Pd nanoparticles promotes the formation and stabilization of Pdδ+ species, optimizing them as adsorption sites for dehydrogenation with appropriate acid strength. Moreover, this interaction adjusts the electronic states of Pd0 active sites, optimizing adsorption dynamics for intermediates. This cooperative action between Pd0 and Pdδ+ significantly boosts the desorption rate of dehydrogenation products, substantially improving the catalysis performance.