Induced chirality in metal porphyrin-based biomimetic catalysts promotes ORR activity by enabling spin-polarization effects

Abstract

Recent research indicates that chirality enables quantum-scale regulation through spin-polarization processes, thereby influencing electron transfer in biological systems. Specifically, heme-containing proteins, namely hemoglobin, myoglobin, and cytochromes, play essential roles in biological redox reactions involved in respiration. These proteins utilize the metalloporphyrin active site to catalyze the oxygen reduction reaction (ORR), and the chiral motif helps in spin-polarized charge transfer during the reduction of triplet oxygen. Inspired by paradigms established by nature, here, we design simple metal–porphyrin complexes, namely cobalt tetra-phenyl porphyrin (CoTPP) and iron tetra-phenyl porphyrin chloride (FeTPPCl), associated with chiral camphor sulfonic acid as biomimetic catalysts for ORR. This study links fundamental principles of biological electron transfer to electrocatalysis, focusing on how chirality and spin polarisation affect the ORR process and aid the progression of catalysts in next-generation energy technologies.