Selective and Stable CO2 Electroreduction to CH4 via Electronic Metal-Support Interaction upon Decomposition/Redeposition of MOF

The CO2 electroreduction to fuels is a feasible approach to provide renewable energy sources. Therefore, it is necessary to conduct experimental and theoretical investigations on various catalyst design strategies, such as electronic metal-support interaction, to improve the catalytic selectivity. Here a solvent-free synthesis method is reported to prepare a copper (Cu)-based metal-organic framework (MOF) as the precursor. Upon electrochemical CO2 reduction in aqueous electrolyte, it undergoes in situ decomposition/redeposition processes to form abundant interfaces between Cu nanoparticles and amorphous carbon supports. This Cu/C catalyst favors the selective and stable production of CH4 with a Faradaic efficiency of approximate to 55% at -1.4 V versus reversible hydrogen electrode (RHE) for 12.5 h. The density functional theory calculation reveals the crucial role of interfacial sites between Cu and amorphous carbon support in stabilizing the key intermediates for CO2 reduction to CH4. The adsorption of COOH* and CHO* at the Cu/C interface is up to 0.86 eV stronger than that on Cu(111), thus promoting the formation of CH4. Therefore, it is envisioned that the strategy of regulating electronic metal-support interaction can improve the selectivity and stability of catalyst toward a specific product upon electrochemical CO2 reduction.

Automated summary

The electroreduction of CO2 to fuels is a viable method for renewable energy sources. This study investigates various catalyst design strategies, such as electronic metal-support interaction, to improve catalytic selectivity. A solvent-free synthesis method is used to prepare a copper-based metal-organic framework (MOF) that undergoes in situ decomposition/redeposition processes upon CO2 reduction, forming interfaces between Cu nanoparticles and amorphous carbon supports. This Cu/C catalyst shows high selectivity and stability in producing CH4, with a Faradaic efficiency of approximately 55% at -1.4 V versus reversible hydrogen electrode (RHE) for 12.5 h. Density functional theory calculation demonstrates the importance of interfacial sites between Cu and amorphous carbon support in stabilizing key intermediates for CO2 reduction to CH4. Adsorption of COOH* and CHO* at the Cu/C interface is significantly stronger than on Cu(111), promoting CH4 formation. Therefore, regulating electronic metal-support interaction can improve the selectivity and stability of catalysts for electrochemical CO2 reduction.