Transition-Metal-Doped SiP₂ Monolayer for Effective CO₂ Capture: A Density Functional Theory Study

Area of Science:

• Materials Science
• Environmental Science
• Chemistry

Background:

• Two-dimensional materials offer potential for climate change mitigation via carbon dioxide (CO2) sensing and capture.
• Orthorhombic silicon diphosphide (SiP2) possesses advantageous properties like high carrier mobility, piezoelectricity, and mechanical stability, yet its CO2 interaction is unstudied.

Purpose of the Study:

• To investigate the adsorption of CO2 on pristine and doped SiP2 monolayers.
• To evaluate the potential of doped SiP2 for CO2 capture and removal applications.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Adsorption energies, band structures, partial density of states, and charge transfer were analyzed for pristine and Ti-, V-, and Cr-doped SiP2.

Main Results:

• Doped SiP2 systems demonstrated significantly stronger CO2 adsorption energies (-0.268 to -0.396 eV) compared to pristine SiP2 (-0.017 to -0.031 eV).
• Low defect formation energies suggest the possibility of synthesizing these doped materials.
• Analysis of electronic properties and charge transfer supported the enhanced adsorption.

Conclusions:

• Titanium- and vanadium-doped SiP2 monolayers show promise as effective materials for CO2 capture and removal.
• The enhanced adsorption capabilities stem from the doping effects on the electronic structure of SiP2.
• These findings contribute to the development of advanced materials for environmental remediation.