Quantum Chemical Study on the Temperature Dependence of Separation of Molecular Hydrogen and Deuterium Using
Hao Xue1, Naoki Kishimoto1, Shinya Takaishi1
1Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan.
Abstract:
Molecular hydrogen is considered an ideal next-generation energy carrier. There are two methods of hydrogen molecule adsorption: chemical adsorption and physical adsorption. Since chemical adsorption is strong and physical adsorption is weak, an intermediate adsorption mode is necessary to achieve reversible adsorption and desorption at room temperature. In this study, quantum chemical calculations were used to investigate a solid-phase manganese hydrogen complex, [Mn(CO)(dppe)2-H2]+ (referred to as Mn1, and dppe = 1,2-bis(diphenylphosphino)ethane), to determine whether reversible adsorption and desorption at temperature relatively close to room temperature is feasible. Furthermore, since the adsorption energy for D2 is not the same as that for H2, the feasibility of separating D2 and H2 was explored by Gibbs energy calculations at different temperatures using the density functional theory. Based on adsorption measurements conducted at 310-365 K, the D2/H2 separation factor for Mn1 ranged from 2 to 1.5 as observed in our previous study. The results calculated using the M06-2X functional indicated that the D2/H2 separation factor for Mn1 at 298 K was approximately 2.55, which is superior to the results obtained using the B3LYP and CAM-B3LYP functionals. The isotope separation ability of [Mn(CO)3(PCy3)2-H2]+ (referred to as Mn2) is slightly inferior to that of Mn1; however, it has an advantage of lower adsorption enthalpy compared to Mn1, making it more suitable for desorption at lower temperatures.
More Related Videos
05:51Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
08:40Millisecond Hydrogen/Deuterium-Exchange Mass Spectrometry for the Study of Alpha-Synuclein Structural Dynamics Under Physiological Conditions
Published on: June 23, 2022
Related Concept Videos
¹H NMR of Labile Protons: Deuterium (²H) Substitution
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
Molecular Orbital Theory II
Hess's Law
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
