Transforming main-group elements into highly active single-atom electrocatalysts for oxygen reduction reactions

Abstract

Despite their potential as electrocatalysts, the catalytic mechanisms of main-group single-atom catalysts (MSACs) remain largely unexplored. To address this knowledge gap, we conducted a series of first-principles calculations to investigate a repertoire of MSACs that incorporated 17 active main-group atoms and 8 carbon supports, systematically screening the optimal catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) via activity-adsorption scaling relations. Our findings reveal that as the single-atom in MSACs moves down the periodic table, their adsorption capabilities become even more enhanced. Moreover, MSACs derived from the fifth and sixth periods exhibit mild adsorption capabilities and robust catalytic activity. In addition, our study identifies a linear correlation between the adsorption energy of *OH intermediates, the p-band center, and the electronegativity of the main-group atom in MSACs, serving as an efficacious ORR activity descriptor and allowing for the prediction of novel catalysts. Our analysis further illuminated two distinct interaction patterns of MSACs with oxygenated species, elucidated through studying the px- and pz-band centers and the resulting effects of orbital hybridization. Moreover, we successfully delineated the regulator role of carbon support species in enhancing the adsorption abilities of MSACs. By strategically pairing the appropriate main-group atoms with suitable carbon supports, we propose an innovative approach for the design of high-performance MSAC catalysts.