We first recorded the DPV curves with PdGa-A crystal in the electrolyte with and without L-DOPA (Fig. ). One can see clearly the strong and well-defined DOPA oxidation peak at around 0.72 V. On the other hand, there are no significant changes for the peak corresponding to the formation of Pd-O and Pd-OH bonding at the lower potential of about 0.51 V. These features are fully consistent with the CV scanning results. The same results are found when the PdGa-B crystal was used (Fig. ). This uncourtly confirmed the oxidation of DOPA at the surface PdGa crystals. Next, we measured the chirality-dependent oxidation of DOPA with PdGa-A and B crystals, respectively. As summarized in Fig. , the oxidation currents for L-DOPA and D-DOPA are inversed at the surface of PdGa-A and PdGa-B crystals. In other words, the oxidation of L-DOPA at the surface of PdGa-A crystal is more favorable than D-DOPA, while PdGa-B crystal prefers the oxidation of D-DOPA. These results suggest that the oxidation of DOPA enantiomers is strongly dependent on the chirality of the PdGa crystals because all the other experimental details are kept the same. As an additional testimony, DOPA oxidation behaviors at the surface of archival Pt foil were recorded (Fig. ). There is no sign of enantiomer selectivity from the identical oxidation currents, which is consistent with previous studies. (Note: the potentials for DOPA oxidation are strongly dependent on the electrode properties and measurement conditions. The theoretical standard electrode potential of DOPA oxidation is 0.75 V vs RHE. The experimental values under acidic conditions are 0.76 V for Pt, 0.82V for glassy carbon, 0.85 V for Au electrode, 0.89 V for homocysteine modified Au electrode, , and 1.01 V for 2,20-Bis [2-(5,20-bithienyl)]-3,30-bithianaphthene oligomers coated glassy carbon ) Although the discrimination between two DOPA enantiomers is available with the bulk PdGa single crystals, the differences are not that so pronounced. This may be caused by two reasons. First, side reactions such as PdGa oxidation and radical adsorption happen in the potential window of DOPA oxidation (0.6-1 V vs RHE), which will influence the resolution. Second, besides the main surface of (111), other crystal surfaces and edges are inevitable for the investigated PdGa bulk crystals. This will make the determination of the DOPA oxidation currents more challenging. Wo notice that for the cubic B20 binary crystals with space group 198, the threefold rotation symmetry is along the [111] direction, endowing the (111) surface with exotic electronic properties such as the circular photo-galvanic effect. Thus, it is expected that (111) surface polar surface should have the maximum response towards chiral molecules' adsorption and reaction. With this in mind, one may expect enhanced enantioselectivity by only exposing the (111) chiral surface area. High-quality single-crystalline RhSi (111) thin films with a thickness of 40 nm were synthesized (Fig. ). CV investigation confirmed the oxidation of both L-and D-DOPA (Fig. ). As expected, DPV curves exhibited well-defined DOPA oxidation peaks at around 0.6 V, suggesting the high enantioselective recognition ability at the polar (111) surface (Fig. ).