Triggering the Direct C-C Coupling of Gaseous CO into C₂Oxygenates by Synergizing Interfacial Interactions and Reversible Spatial Dynamic Confinement

Controllable C-C coupling is the key to the transformation of C1 molecules into high-value multicarbon (C₂₊) chemicals. Herein, we report a synergistic mechanism of interfacial metal-support interactions and reversible spatial dynamic confinement that triggers the direct C-C coupling of gaseous CO and further electrical reduction to C₂products over graphene-coating copper-base Gr/Cu(111) electrodes. The interfacial interaction and spatial distance of Gr/Cu(111) dynamically changed by making the interfacial C-Cu bonds between graphene and Cu substrate and breaking these bonds. Such dynamic and synergetic effects enabled not only exceptionally high stability in the hydrogenation of the key intermediate O*C*CO but also led the active sites to become highly adaptable toward both reactant adsorption and product desorption, thus boosting the direct C-C coupling of gaseous CO and selectivity of C₂products. The Gr/Cu(111) electrode surface was favorable for the formation of two-carbon-chemisorbed key intermediate O*C*CO that was formed from two gaseous CO monomers via a metastable intermediate of O*CCO with an energy barrier of 0.94 eV. The O*C*CO and O*CCO configurations chemisorbed on Gr/Cu(111) exhibited a negative univalent [C₂O₂]^-, which was more stable than neutral C₂O₂. The electroreduction pathway of O*C*CO indicates that the formation of acetaldehyde (CH₃CHO) was preferred due to the lowest formation free energy of 0.20 eV, while CH₂CH₂and CH₃CH₂OH were considerably competitive products because their formation free energies were only ∼0.04 eV higher than that of acetaldehyde. The results revealed that such an interfacial dynamic effect granted high catalytic performance, providing an avenue to rationally design novel catalysts and controllable C-C coupling for the electroreduction of CO₂or CO.