In Situ Surface-Enhanced Raman Spectroscopy of CO₂ Reduction by Metal-Organic Framework-Derived Copper Electrode

By pyrolyzing Cu-based MOFs, a Cu⁰/Cu⁺¹/C/N catalyst with a porous carbon layer coating was synthesized. The combination of the Cu ion-rich active sites derived from MOFs and the Raman signal enhancement associated with Cu nanostructures and charge–transfer interactions, which contributes to the SERS effect, was utilized for in situ investigation of the electrochemical CO₂ reduction reaction (CO₂RR) process. This study focuses on the catalytic performance and reaction mechanisms of Cu-MOF-derived materials in the electrocatalytic CO₂ reduction reaction, using in situ Raman and SERS techniques for real-time monitoring and characterization. The results indicate that Cu-MOF-derived materials significantly enhance the selectivity toward C₂ products by tuning the valence state distribution of copper (Cu(I)/Cu(0)) and the structure of active sites. Moreover, the porous carbon-coated Cu elements exhibit stable catalytic performance during the electrocatalytic process (inhibiting hydrogen evolution reaction and stabilizing the valence state of Cu ions). In addition, in situ spectroscopy reveals the dynamic evolution of key intermediates (such as *CO and *CHO) and the ion adsorption process on the catalyst surface, providing crucial insights into the catalytic behavior of Cu-MOF-derived materials.