Green synthesis of Ru nanocatalysts: Characterization and catalytic application in the hydrolysis reaction of ammonia borane

In this study, carbon quantum (CQD)-supported and Ru-based nanocatalysts were synthesized as highly active catalysts for the hydrolytic dehydrogenation of ammonia borane (AB) at room temperature. The readily synthesized catalysts were named as Ru@CQD-TCA and Ru@CQD-ATCA, and advanced analytical methods such as UV-visible region spectroscopy, electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts. These analytical methods revealed that the catalysts were well dispersed on the CQD with average particle sizes of 3,17 nm and 1,2 nm. However, the Ru@CQD-TCA catalyst had a TOF of =297 min-1 and a hydrogen production rate of 55260 mL min-1 at 25 oC, while the Ru@CQD-ATCA catalyst had a TOF = 410 min-1 and a hydrogen production rate of 102100 mL min-1. The present work presents detailed kinetic studies of the hydrolytic dehydrogenation of AB catalyzed by Ru@CQD-TCA and Ru@CQD-ATCA, the results of catalytic experiments were carried out at different temperatures, substrate and catalyst concentrations. Here, the kinetic parameters of Ru@CQD-TCA and Ru@CQD-ATCA catalysts were found that the activation energy (Ea)= 39,26 kJ/mol, the activation enthalpy ΔH# = 36,69 kJ/mol and the activation enthalpy ΔS# = -69,2 J/mol.K for Ru@CQD-TCA catalyst. The activation energy of Ru@CQD-ATCA catalyst was 22,22 kJ/mol, ΔH# = 19,65 kJ/mol and the activation enthalpy was ΔS#= -29,65 J/mol.K.