Synergistic Effect of Pt/Co Dual Clusters on Covalent Organic Frameworks for Highly Selective Photocatalytic CO2 Reduction to Ethylene

To address the critical challenges of sluggish C-C coupling kinetics and the propensity for over hydrogenation to ethane (C2H6) in the photocatalytic CO2 reduction to ethylene (C2H4), this study designed a synergistic bimetallic Pt/Co cluster catalyst supported on a covalent organic framework (COF), designated as PtCo-TpBD COF. This catalyst is designed to modulate the adsorption of key intermediates via Co clusters to suppress over-hydrogenation, while leveraging Pt clusters to promote C-C coupling, thereby achieving highly selective C2H4 production. Through a series of structural characterization analyses, it was confirmed that Pt/Co clusters were successfully confined within the pores of the COF, and significant electronic interactions were observed. In situ infrared spectroscopy revealed that the introduction of Co clusters effectively weakens the adsorption strength of the CO* intermediate, while the incorporation of Pt clusters promotes C-C coupling. In visible-light-driven gas-phase CO2 reduction, this catalyst delivered exceptional activity, reaching an C2H4 formation rate of 7.54 μmol g−1 h−1 and an C2H4 selectivity of 90.1%, along with remarkable inhibition of deep hydrogenation byproducts including C2H6. This study not only provides a successful example for constructing efficient bifunctional photocatalysts to achieve highly selective conversion of CO2 to C2H4, but also highlights the great potential of COFs as advanced platforms for integrating multifunctional metal clusters and precisely tuning catalytic selectivity.