Reactive force field study of the molecular structure of water under thermal and electric effects: Water splitting phenomenon

• Published in: International journal of hydrogen energy Vol. 42; no. 8; pp. 4774 - 4781
• Main Authors: López-Plascencia, C.E., Martínez-Negrete-Vera, M., Garibay-Alonso, R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 23.02.2017
• Subjects: Hydrogen generation mechanisms; Molecular dynamics; Reactive force fields; Water splitting; Hydrogen generation mechanisms; Molecular dynamics; Water splitting; Reactive force fields
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2016.12.073

The molecular structure of water under thermal and electric field effects is determined by using molecular dynamics simulation within a reactive force field and a charge equilibration schema. Focusing the study around the solid and liquid phases, oxygen–oxygen, oxygen–hydrogen and hydrogen–hydrogen radial distribution functions are calculated for several temperatures and applied electric fields. The calculated radial distribution functions signal the conventional solid–liquid and liquid–gas phase transitions of water, including its well known volumetric expansion at the melting point. The temperature driven water splitting phenomenon as well as the diatomic hydrogen formation is clearly observed at the solid and liquid phases of water through the calculated molecular structure. The water splitting behavior and diatomic hydrogen formation is enhanced by the application of homogeneous electric fields with values comparable to those occurring in common electrolysis experimental setups. Additionally, a melting-like process induced by the application of the electric field is observed. •Realistic NPT molecular dynamics taking into account the dissociative molecular properties of water.•A more complete coverage of the thermodynamic parameters related to water splitting.•It correctly describes the water splitting process and the formation of the hydrogen and oxygen species.