Cascade Design and Facile Fabrication of Cu/Cu2O/CuAl‐Layered Double Hydroxides as Efficient Nitrate Reduction Electrocatalysts

Abstract Nitrate (NO 3 ¯) reduction reaction (NITRR) presents a promising pathway for the production of renewable NH 3 while concurrently decontaminating NO 3 ¯ wastewater. However, the multi‐electron transfer sequence and complex reaction network involved in NO 3 ¯ conversion pose significant challenges to achieving high Faradaic efficiency ( FE ). Herein, this work presents ternary Cu/Cu 2 O/CuAl‐layered double hydroxides (LDHs) catalysts designed through a cascade approach and synthesized via a straightforward one‐step electrodeposition method. The resulting catalysts demonstrate peak activity at −0.4 V versus RHE, achieving an impressive of 92.0%, which significantly surpasses most reported binary and ternary catalysts. Density functional theory calculations and atomic force microscopy reveal that the Cu/Cu 2 O/CuAl‐LDHs exploit cascade design by integrating three distinct functions essential for efficient NO 3 ¯ reduction: CuAl‐LDH initiates NO 3 ¯ adsorption, Cu(111) and Cu₂O(111) cooperatively facilitate NO 3 ¯ activation, and Cu(111) promotes NH 3 desorption. Durability tests further confirm that both NH 3 yield and remain stable after 10 cycles, indicating the excellent stability of the Cu/Cu 2 O/CuAl‐LDHs catalysts. These findings underscore the critical role of cascade design strategies in enhancing the performance of electrocatalysts for NO 3 ¯ reduction to NH 3 , providing a transformative approach for sustainable ammonia synthesis.