Quantum Chemical Calculations on the Reaction of Zinc and Water in Gas Phase

Abstract

The reaction of zinc with water is one of two steps of the Zn/ZnO water-splitting thermochemical cycle and is of interest for the hydrogen production. The reaction of zinc with water was investigated here by ab initio quantum chemical methods, and the results provided fundamental understanding of the zinc oxide particle formation in the gas phase. The geometries and frequencies of all reactants, products, intermediates, and transition states were calculated at the B3LYP/6-311G++(3df, 2p) level. The Zn and water first form an atom–molecule adduct Zn · OH₂, and then either form HZnOH by an H-migration process or directly form ZnO + H₂ by an H-dissociation process. The higher-level energies, barrier heights of the two paths, and rate constants were calculated. The results showed that H-migration process was dominant in the studied temperature range.

Keywords:

• Hydrolysis
• Quantum chemistry
• Rate constant
• Reaction mechanism
• Zinc

ACKNOWLEDGMENT

The authors are thankful to Prof. Donald G. Truhlar, Department of Chemistry, University of Minnesota, for the license access to the POLYRATE program.

Notes

i: imaginary frequency.

^a Kauffman et al., 1985.

^b Macrae et al., 2004.

1: B3LYP/6-311++G(3df, 2p).

2: MP4/6-311++G(3df, 2p).

3: QCISD(T)/6-311++G(3df, 2p).

4: CCSD(T)/6-311++G(3df, 2p).

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