Ionic Diffusion inCO2Adsorption byLi4⁢SiO4: Inert-Marker Experiment and DFT Calculations

Abstract

CO2 adsorption by Li4⁢SiO4 has garnered significant attention for its potential in effectively capturing CO2. The slow diffusion-controlled reaction within the product layer is a key factor affecting CO2 adsorption. However, no research has been conducted to study the diffusion mechanism. Here, ionic diffusion was systematically comprehended through inert-marker experiments and first-principles calculations. An electron probe test clearly captures the movement of inert-marker Pt into the product layer, thus the outward transfer of O2− and Li+ ions is proposed to be the dominant diffusion mode. Density functional theory calculations also confirm the diffusion of O2− and Li+ with the former being the speed controlling step.