Ferroelectric-enabled significant carbon dioxide molecular adsorption on BaTiO3(001)†

Carbon dioxide (CO₂) is reversibly adsorbed and desorbed from ferroelectric (001) oriented, BaO-terminated barium titanate, as revealed in real time by high resolution and ultrafast photoelectron spectroscopy and certified by low energy electron diffraction. Desorption proceeds when the substrate is heated above its Curie temperature. The amount of CO₂ adsorbed is derived to be between one molecule for a surface BaO unit cell (adsorption below room temperature) and one molecule for two unit cells (adsorption above room temperature). The molecule is bound with its carbon to surface oxygen, forming a CO₃ structure. The BaTiO₃(001) surface is unaffected by repeated cycles of adsorption–desorption. The relatively high amount of CO₂ adsorbed and the stability of the substrate after repeated adsorption and desorption processes promotes barium titanate as a promising candidate for decarbonization technologies.