Tandem catalysis on adjacent active motifs of copper grain boundary for efficient CO2 electroreduction toward C2 products

Copper (Cu) is a special electrocatalyst for CO2 reduction reaction (CO2RR) to multi-carbon products. Experimentally introducing grain boundaries (GBs) into Cu-based catalysts is an efficient strategy to improve the selectivity of C2+ products. However, it is still elusive for the C2+ product generation on Cu GBs due to the complex active sites. In this work, we found that the tandem catalysis pathway on adjacent active motifs of Cu GB is responsible for the enhanced activity for C2+ production by first principles calculations. By electronic structure analysis shows, the d-band center of GB site is close to the Fermi level than Cu(100) facet, the Cu atomic sites at grain boundary have shorter bond length and stronger bonding with *CO, which can enhance the adsorption of *CO at GB sites. Moreover, CO2 protonation is more favorable on the region III motif (0.84 eV) than at Cu(100) site (1.35 eV). Meanwhile, the region II motif also facilitate the C–C coupling (0.72 eV) compared to the Cu(100) motif (1.09 eV). Therefore, the region III and II motifs form a tandem catalysis pathway, which promotes the C2+ selectivity on Cu GBs. This work provides new insights into CO2RR process.