Graphical abstract

Unequivocal evidence of enantioselective, equilibrium separation of a racemic mixture on a naturally chiral metal surface is presented for the first time. The enantioselectivity is much higher than that of chiral molecules on mineral surfaces. Furthermore, the quantitative nature of the ¹³C labeling method provides the first direct measure of an enantiospecific adsorption energy difference on a chiral metal surface.