AB Initio kinetics of the reactions between BH4− + OH•

Abstract

Tetrahydroborate anion (BH4-) in Td symmetry group is a well-known hydrogen carrier, involved in various reactions to produce hydrogen gas. In this work, we reassessed the mechanism and kinetics of reactions between BH4- + OH• by using the DFT study. All of the structures in this reaction are optimized using the M062X/6-311++G(d,p) method. The solvent effect on the reaction mechanism was also taken into account by using the solvation model density (SMD). Based on the potential energy surfaces, the rate constants were also estimated by using the transition state theory (TST). It was discovered that the BH4- efficiently captures the free radical OH• in the gas phase. In an aqueous solution at a pressure of P = 1 atm and temperature of T = 298.15 K, the title reaction is controlled by diffusion effects, with a rate constant of kD = 9.4 ´ 109 M-1s-1.

Keywords

• tetrahydroborate anion
• mechanism
• dft calculations
• tst
• kinetics