p–d Orbital coupling in silicon-based dual-atom catalysts for enhanced CO2 reduction: insight into electron regulation of active center and coordination atoms

Abstract

Transition metal (TM) dual-atom catalysts (DACs) show promise for carbon dioxide reduction reaction (CO₂RR) through d–d orbital cooperative interactions, but their effectiveness is often curtailed by the linear scaling relations between *CO and *CHO on transition metal sites, typically resulting in CO as the predominant product. Specifically, the p–d orbital coupling may exert further influence to regulate the electronic properties and catalytic activity of DACs, which will be of great significance for promoting CO₂RR. Herein, we combine density functional theory (DFT) and machine learning (ML) to investigate the potential of heteronuclear DACs with the Si-TM dual-atom active sites in CO₂RR and evaluate the influence of the coordination environment. Among 27 SiTMN₆ and 336 SiTMN₅An (A = B, C, and n represents position) DACs, three SiTMN₆ and six SiTMN₅An DACs demonstrate high activity and selectivity in converting CO₂ to CH₄ or CH₃OH. The p_z band distribution , influenced by both p–d orbital coupling and the coordinating environment, has been elucidated. The optimal results in superior reaction activity by facilitating optimal adsorption effects for reaction intermediates. This work not only provides comprehensive understanding of reaction mechanisms for CO₂ reduction on silicon-based dual-atom catalysts, but also reveals the irreplaceable role of p–d coupling in the performance regulation of DACs. With this knowledge and the aid of machine learning, we establish fundamental principles and descriptors for the accelerated discovery of efficient dual-atom catalysts.