Zerovalent Selenium Adsorption Mechanisms on CaO Surface: DFT Calculation and Experimental Study.

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Understanding selenium adsorption is crucial for environmental remediation and materials science.
• Calcium oxide (CaO) is a widely studied material with potential applications in catalysis and adsorption.

Purpose of the Study:

• To investigate the adsorption mechanisms of zerovalent selenium (Se) on a calcium oxide (CaO) surface.
• To elucidate the fundamental interactions between Se and CaO at the atomic level.

Main Methods:

• Density functional theory (DFT) calculations were performed using a slab model to simulate Se adsorption on the CaO(001) surface.
• Adsorption experiments were conducted in a quartz reactor at 300 °C.
• Characterization techniques included X-ray photoelectron spectroscopy (XPS), ICP-AES, FE-SEM/EDS, and XRD.

Main Results:

• DFT calculations determined adsorption energy, structure, electron density, and properties for different Se coverages.
• Experimental results from XPS, ICP-AES, FE-SEM/EDS, and XRD corroborated the theoretical findings.
• Both methods confirmed monochemisorption as the primary adsorption mechanism.

Conclusions:

• Zerovalent selenium undergoes monochemisorption on the CaO surface.
• The combination of DFT calculations and experimental validation provides a comprehensive understanding of Se-CaO interactions.