期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：30
DOI：10.1073/pnas.2202650119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
The oxygen reduction reaction is essential to aerobic respiration and is a fundamental chemical reaction in fuel cells. The reaction converts triplet oxygen to products that are all in singlet electronic states, and its understanding requires spin considerations. We show that the oxygen reduction can be enhanced by controlling the spin of the electrons transmitted to the oxygen. We achieve this control by using a chiral electrode and the chiral-induced spin selectivity effect to direct the reaction efficiently on a triplet potential energy surface. This mechanistic feature may help explain the efficiency of respiration in living organisms, which contain chiral enzymes, and provides a strategy for improving catalyst efficiency in fuel cells.
Controlled reduction of oxygen is important for developing clean energy technologies, such as fuel cells, and is vital to the existence of aerobic organisms. The process starts with oxygen in a triplet ground state and ends with products that are all in singlet states. Hence, spin constraints in the oxygen reduction must be considered. Here, we show that the electron transfer efficiency from chiral electrodes to oxygen (oxygen reduction reaction) is enhanced over that from achiral electrodes. We demonstrate lower overpotentials and higher current densities for chiral catalysts versus achiral ones. This finding holds even for electrodes composed of heavy metals with large spin–orbit coupling. The effect results from the spin selectivity conferred on the electron current by the chiral assemblies, the chiral-induced spin selectivity effect.
