Adsorption and dissociation behavior of water on pristine and defected calcite {104} surfaces: A DFT study

Highlights: • Elemental doping and interstitial O are most easily generated defects on calcite (1 0 4). • Water adsorption is apparently enhanced by the calcite (1 0 4) surface defects. • Water is easily dissociated on - CO₃ vacancy defected calcite (1 0 4) surface. • The activation energy of water dissociation is greatly related to the ICOHP of the dopants - O of water atom pairs. Defect-dominated regulation on water adsorption or dissociation on calcite surface is crucial in several important areas including the geochemistry of calcite, haze formation, which is caused by calcite based mine dust, inorganic material design and so on. Here, density functional theory (DFT) method has been utilized to systematically investigate the behavior of water on various calcite {1 0 4}surfaces, focusing on the effect of defects, including doping defected (Co-, Mg-, Mn-, Zn-, and Cu-doped), vacancy-defected (Ca or CO₃), and the interstitial O calcite {1 0 4} surfaces. As demonstrated, although all the defects enhance the water adsorption, the enhancement degree varies with the defects type that the vacancy defects exhibit more remarkable role. The activation energy of water dissociation is greatly related to the integrated crystal orbital Hamilton populations (ICOHP) energy of the dopants - O of water atom pairs in the water-calcite {1 0 4} surface interaction systems. It indicates that water is easily dissociated on - CO₃ vacancy-defected calcite {1 0 4} surface. Our study can be helpful for the understanding of the water adsorption and dissociation on defected calcite surfaces.