AuCu Nanodendrite for Enhancing Electrocatalytic Nitrate Reduction Applications via Two-stage Microfluidic Fabrication Strategy

Abstract

The electrocatalytic nitrate reduction reaction (NitrRR) has attracted great attention in clean ammonia production, but it has unsatisfactory selectivity and sluggish dynamics, owing to the complex eight-electron transfer process. While dendritic AuCu alloy is anticipated to offer competitive performance, significant challenges remain in terms of insufficient structural regulation and an unelucidated reaction enhancement mechanism because of the complexity involved in its preparation. To address these issues, we have developed a two-stage microfluidic platform that facilitates the stable fabrication and controllable regulation of AuCu nano dendrites (NDs). Notably, the Cu content in the resultant AuCu NDs reaches an impressive 35.34 At%, surpassing traditional liquid-phase reduction limitations. Furthermore, the dendrite structure has been thoroughly validated, revealing a clear structure–activity relationship. By employing precise manipulation, we have determined the optimal composition of AuCu NDs, achieving a remarkable ammonia yield of 21.93 mg h^–1 cm^–2 and a faradic efficiency of 93.30%. Additionally, DFT calculations further elucidate the performance enhancement mechanism, showing that Au₃Cu₁ sites in the AuCu NDs significantly reduce the energy barrier (0.28 eV) of the rate-determining step (RDS: *NO → *HNO), while excessive Cu deposition has an adverse effect. Our work contributes innovative guidance for the design and controllable fabrication of high-performance electrocatalysts.