Main-Group Metal Elements as Promising Active Centers for Single-Atom Catalysts

TL;DR

This study explores the potential of main-group metals as active centers in single-atom catalysts for NO reduction, revealing new candidates and mechanisms that expand the scope of SACs beyond transition metals.

Contribution

It introduces a high-throughput computational approach to identify main-group metal SACs, demonstrating their viability and elucidating the physical mechanisms involved.

Findings

Identified six high-activity main-group metal SACs for NORR.

Demonstrated the importance of s/p-band filling in catalytic performance.

Established NO adsorption energy as a key descriptor for SAC activity.

Abstract

Current research efforts on single-atom catalysts (SACs) exclusively focus on nonmetal or transition-metal atoms as active centers, while employing main-group metal elements is seemingly excluded because their delocalized s/p-bands are prone to yield a broadened resonance for the interaction with adsorbates. Here, we use high-throughput first-principles calculations to investigate the possible incorporation of Mg, Al and Ga to form graphene-based SACs for NO reduction reaction (NORR) toward NH3. 51 SAC candidates with different metal coordination environment have been computationally screened employing a rationally designed four-step process, yielding six SACs with high catalytic activity and NORR selectivity. The performance is rationalized by the modulation of s/p-band filling of the main-group metals. The adsorption free energy of NO is identified as efficient descriptor for such SACs. The underlying physical mechanism is revealed and generally applicable to other main group metal SACs. These fundamental insights extend SACs to main-group metal elements.