Water-Promoted CO₂ Adsorption on the ZrO₂(001) Surface: A First-Principles Mechanistic Study

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Direct air capture (DAC) is crucial for negative carbon emissions.
• Atmospheric CO2 coexists with water vapor, influencing capture performance.
• Zirconium dioxide (ZrO2) is a promising support for DAC adsorbents, but its behavior under humid conditions is not fully understood.

Purpose of the Study:

• To investigate the adsorption mechanisms of CO2 and H2O on the ZrO2(001) surface.
• To elucidate the synergistic effects between CO2 and H2O during adsorption.
• To understand the atomic and electronic-scale interactions for improved DAC material design.

Main Methods:

• First-principles calculations were used to model adsorption.
• Systematic investigation of single CO2, single H2O, and CO2+nH2O (n=1-4) adsorption.
• Analysis of adsorption energies, interaction energies, and electronic structures.

Main Results:

• Pristine ZrO2(001) shows weak intrinsic CO2 adsorption.
• Water molecules significantly enhance CO2 adsorption through synergistic effects, especially when n > 2.
• Water modifies interfacial interactions and electronic properties, improving CO2 binding.

Conclusions:

• Water plays a critical role in enhancing CO2 adsorption on ZrO2 surfaces.
• Understanding CO2/H2O co-adsorption mechanisms at the atomic level is key for designing efficient DAC materials.
• This work provides a theoretical foundation for developing advanced ZrO2-based adsorbents for direct air capture.