Atomically Dispersed Alkaline‐Earth Metals as Active Centers for CO2 Electroreduction to Exclusively Produce Formate

Abstract

Electrocatalytic CO2 reduction reaction (CO2RR) to produce formate (HCOOH) attracts special interest in the upgrade of waste CO2. For the selective CO2 conversion into HCOOH, the preferable binding of *OCHO compared with *COOH is a prerequisite, which presents a great challenge to the rational design of the catalytic active center. Recently, alkaline‐earth (AE) metals as active centers have been reported for electrocatalysis. Herein, the feasibility of AE metals as active centers in heterogeneous catalysis for electrocatalytic CO2RR toward HCOOH based on a series of AE metal single‐atom catalysts (SACs) is theoretically studied. High‐throughput first‐principles calculations reveal that, for all the studied systems, the AE metal active centers preferably adsorb *OCHO, enabling exclusive HCOOH production. Especially, Mg SACs embedded in graphene and Ca SAC anchored in g‐C2N can efficiently convert CO2 into HCOOH under near‐zero potential, and both systems exhibit high stability. Mechanistic investigation indicates that the AE metal active centers are highly ionic, which can strongly bind *OCHO mainly through the electrostatic attraction interaction. This study lays a theoretical foundation for the rational design of AE metal SACs for efficient CO2 electroreduction with exclusive HCOOH selectivity, and further emphasizes the potential of AE metals as active centers in heterogeneous catalysis.

Keywords

• alkaline-earth metals
• electrocatalytic CO2 reduction reactions
• first-principles calculations
• formate
• single-atom catalysts