Intrinsic Descriptors for Coordination Environment and Synergistic Effects of Metal and Environment in Single-Atom-Catalyzed Carbon Dioxide Electroreduction

Abstract

Activity of heterogeneous single-atom catalysts (SACs) depends on both the active center and the coordination environment. Previous studies focus more on the former. In this study, we systematically examine CO2 reduction reaction (CO2RR) catalyzed by SACs with different coordination environments on graphene. We find that carbon and nitride coordination generally leads to higher activity compared to phosphorus and sulfur coordination. C, N-rich environment is more likely to produce CO, while P, S-rich environment prefers HCOOH production. Two intrinsic descriptors, namely, average number of electrons in outer p-orbitals and average third ionization energy, are identified to describe coordination environment. Furthermore, two intrinsic descriptors are proposed to describe the synergistic effects of metal active center and coordination environment. By checking available data in the literature, we confirm that these descriptors are quite universal for CO2RR. Part of them is even suitable for oxygen reduction reaction (ORR). This study opens a new avenue to screen high performance SACs based on intrinsic properties of the metal and environmental elements.