Revisiting Water Adsorption on TiO₂ and ZnO Surfaces: An SCC-DFTB Molecular Dynamics Study

Area of Science:

• Materials Science
• Environmental Chemistry
• Computational Chemistry

Background:

• Metal oxides (MOs) are crucial in biomedicine and industry.
• Assessing MO toxicity, especially in aquatic environments, is vital.
• Surface electronic structure dictates MO reactivity and potential toxicity.

Purpose of the Study:

• To investigate the interaction between metal oxide surfaces and water.
• To understand how surface electronic and geometric structures influence reactivity.
• To identify potential toxicity descriptors for metal oxides.

Main Methods:

• Simulated the interaction of Zinc Oxide (ZnO) and Titanium Dioxide (TiO2) slab models with water.
• Employed density functional tight binding theory (DFTB).
• Utilized finite temperature molecular dynamics (MD) simulations.

Main Results:

• Observed changes in geometric and electronic structures at the MO-water interface.
• Analyzed water interaction under varying conditions (temperature, surface hydrogenation).
• Identified critical surface points initiating dissolution processes.

Conclusions:

• Provided molecular-level insights into MO surface topographical and electronic processes.
• Revealed potential toxicity descriptors through systematic analysis.
• Highlighted the importance of surface electronic structure in MO environmental impact assessment.