Chiral-Encoded Pt-Ir Surfaces as Apparent Spin Filter for Enhanced Oxygen Reduction.

Chiral Induced Spin Selectivity (CISS) is a promising effect for enhancing the electrochemical oxygen reduction reaction (ORR), an essential process in clean energy technologies. So far, the concept has been validated mostly for surfaces modified with chiral organic layers; however, it remains unexplored for chiral metal matrices. Here, we study chiral-encoded mesoporous Pt-Ir alloys, bearing high selectivity when used for the analysis, separation, and synthesis of enantiomers. We demonstrate a very substantial difference in ORR activity for Pt-Ir electrodes imprinted with molecules of opposite handedness. One enantiomorph catalyzes oxygen reduction, whereas its mirror image surprisingly acts as an inhibitor. This very unusual asymmetric reactivity is due to an interplay between the CISS effect and the adsorption of oxygen on the metal surface, leading to a break of symmetry in terms of spin interactions. Our findings open up promising perspectives for designing CISS-based ORR catalysts, advancing the development of clean energy technologies.