Thermodynamic and Kinetic Analysis of Hydrogen Capture in a Homobinuclear Palladium(II) Complex

Abstract

In this work, the homobinuclear complex (di-μ-chlorobis[2-[(dimethylamino)methyl]phenyl-c,n]dipalladium(II)) (1) was synthesized by reacting N,N-dimethylbenzylamine (dmba) with palladium(II) chloride in methanol at room temperature. The prepared complex was characterized using FTIR spectrum, melting point, and ¹HNMR spectrum. The prepared complex was evaluated for its hydrogen storage capacity under different pressures (0–100 bar) and temperatures (77–273 K). The hydrogen storage isotherm revealed that the highest storage value recorded was 3.692 at 77 K and 67 bar. The thermodynamic calculations showed that the enthalpy change was equal to 0.2038 (KJ/mol H₂) while the entropy change was equal to 1.09278 (J/mol H₂. K). The kinetic studies showed that the complex can only store the maximum value (3.692 wt%) in 300 s at 173 K. The kinetic study showed that the R² value was 0.4884 and 0.967 for the pseudo-first order and pseudo-second order reactions, respectively. According to the Langmuir model, this complex formed a strong interaction with hydrogen, as indicated by an R_F value equal to 0.1897.