High stability copper clusters anchored on N-doped carbon nanosheets for efficient CO₂ electroreduction to HCOOH

Cu-based nanomaterials is crucial for electrochemical CO₂ reduction reaction (CO₂RR), but they inevitably undergo performance degradation due to structural self-reconstruction at a large current density during CO₂RR. Here, we developed a pre-synthetic atomically dispersed Cu source strategy to fabricate a catalyst of stable Cu clusters anchored on N-doped carbon nanosheets (c-Cu/NC), which exhibited an exceptional electroreduction for CO₂ to HCOOH with a Faradaic efficiency of up to 96.2 % at current density of 276.4 mA cm^-2 at - 0.96 V vs. RHE, which surpasses most reported catalysts. Especially, there was no any decay in stability during a 100 h continuous test, attributed to a strong interaction of Cu-C for restraining its self-reconstruction during CO₂RR. DFT calculations indicated that N-doped carbon can strongly stabilize Cu clusters for keeping stability and cause the downshift of d-band center of Cu on c-Cu/NC for reducing the desorption energy between c-Cu/NC and OCHO* intermediates. This work provides an effective way to construct stable Cu clusters catalysts, and unveil the origin of catalyticmechanism over Cu clusters anchored on N-doped carbon towards electrochemical conversion ofCO₂ to HCOOH.