It is widely recognized that capturing and storing CO2 on porous materials is an efficient approach for lowering the concentration of this greenhouse gas in the atmosphere. The current work investigates the ability of Ca and Al decorated all-boron B38 fullerene to capture and store CO2 using dispersion-corrected density functional theory calculations. The results showed that Ca and Al atoms can both firmly attach to the boron atoms in the hexagon cavity of B38. This eliminates the clustering issue and may ensure the stability of the decorated B38 fullerenes. According to the findings, the B38 fullerene decorated with four Ca or Al atoms may retain up to 16 CO2 molecules, corresponding to a maximum gravimetric density of about 55 wt%. The adsorption energy per CO2 in the Ca and Al decorated systems is about -0.70 eV, which is within the range proposed for effective CO2 storage. As a result, Ca and Al decorated B38 fullerenes are efficient and promising materials for high-capacity CO2 storage.