Enhancing electrocatalytic CO₂ reduction via engineering substrate-cluster interaction

Cu clusters exhibit exceptional performance in the electrocatalytic carbon dioxide reduction reaction (CO₂RR) due to their tunable size. Using first-principles calculations, we systematically investigate the CO₂RR on small Cu_n clusters (n = 3, 8, 13) anchored on a T'-WTe₂ substrate, denoted as Cu_n@T'-WTe₂. Given that the hydrogen evolution reaction (HER) often competes with the CO₂RR, we further investigated the competition between the CO₂RR and HER. Our results show that Cu_n@T'-WTe₂ outperforms pure Cu_n clusters as catalysts, with enhanced CO₂RR activity. The CO₂RR performance of Cu_n@T'-WTe₂ enhances with increasing cluster size, and surpasses the HER activity in Cu₁₃@T'-WTe₂. This enhancement stems from the substrate-cluster interactions, where the buckled "non-uniform surface" of T'-WTe₂ deforms the larger Cu₁₃ cluster, optimizing the CO₂RR efficiency. We propose a potential strategy for WTe₂-supported Cu clusters to boost CO₂RR while suppressing HER by leveraging substrate-supported Cu clusters.