Magnesium phyllosilicate (Mg-APTES) was developed and explored for its applicability as a potent carbonation catalyst that converts CO2 into carbonate ions. Careful investigation of its surface properties revealed a lamellar structure and the existence of an amine group, which is the expected CO2 capture site. The prepared magnesium phyllosilicate was found to successfully convert gaseous CO2 into HCO3- (bicarbonate ion), actively forming CaCO3 (calcium carbonate) when Ca2+ (calcium ion) was supplied. This study shows that the magnesium phyllosilicate, a new type of carbonation agent and a concept of an artificial mimetic catalyst, can be a good candidate catalyst for CO2 capture.