Diatomic molecule catalysts toward synergistic electrocatalytic carbon dioxide reduction

Synergistic catalysis with diatomic catalysts is an effective means to boost carbon dioxide (CO2) electroreduction efficiency and product selectivity; studies in this field also contribute to an atomic-level understanding of the synergy mechanism. However, the precise design of atoms in diatomic active centers is extremely challenging. Herein, a diatomic-molecule catalyst (DMC), double Co-salophen (D-Co) with a precise Co-Co distance of 0.523 nm, was supported on carbon nanotubes using a non-covalent anchoring strategy. The catalyst exhibits excellent performance in the electrochemical CO2 reduction reaction (CO2RR) with a CO faradaic efficiency of 91.76% at -0.70 V versus a reversible hydrogen electrode (RHE), a turnover frequency of 2056.7 h(-1) at -0.90 V vs. RHE, and good stability. This excellent CO2RR performance is attributed to the synergistic adsorption and activation of H2O and CO2 molecules on both Co atomic sites, which are connected by strong hydrogen bonds. Density functional theory calculations demonstrate that this type of hydrogen bond promotes CO2 activation, stabilizes the intermediate, and decreases the energy barrier. The DMC developed in this study provides a new template and strategy for the precise and rational design and preparation of diatomic molecule catalysts.

Automated summary

This study successfully designed and prepared a precise diatomic catalyst that achieves synergistic adsorption and activation of H2O and CO2 molecules through strong hydrogen bonding, thereby improving the efficiency and product selectivity of CO2 electroreduction.