Catalytic hydrogen production from NaBH4 methanolysis using phosphoramidite-stabilized ruthenium nanoparticles

Here, ruthenium nanoparticles (1@RuNPs, 2@RuNPs, 3@RuNPs) stabilized with monodentate phosphoramidide ligands based on binanaphthyl skeletons with different steric properties (R: methyl(1), ethyl(2) and isopropyl(3)) were synthesized. To our knowledge, this study reports the first use of phosphoramidide ligands as stabilizers for ruthenium nanoparticles and systematically demonstrates their catalytic efficiency in hydrogen production via NaBH 4 methanolysis. Their physical and chemical properties were elucidated using advanced characterization techniques, and accordingly, phosphoramidide ligands effectively stabilize ruthenium nanoparticles, producing particles with a narrow size distribution, small dimensions (1.36-1.41 nm) and a monodisperse structure. The catalytic performance during NaBH 4 solvolysis was investigated, and 2@RuNPs catalyzed NaBH 4 methanolysis 1.48 times faster than the others, reaching a hydrogen production rate of 452.9k mL H 2 /(g cat ∗min) in 10 s (k = 10 3 , HPR 10sec ). During kinetic studies for NaBH 4 methanolysis, activation energies for those catalyzed by 1@RuNPs, 2@RuNPs, and 3@RuNPs were calculated as 19.80 ± 0.53, 25.43 ± 0.27, and 44.57 ± 0.50 kJmol -1 , respectively.