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 Cun clusters (n = 3, 8, 13) anchored on a T'-WTe2 substrate, denoted as Cun@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 Cun@T'-WTe2 outperforms pure Cun clusters as catalysts, with enhanced CO2RR activity. The CO2RR performance of Cun@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.