3D‐Printed CuNi Self‐Supporting Electrocatalysts with Ordered Microchannels for Ammonia Production

ABSTRACT Self‐supporting catalysts have attracted massive research interest in electrocatalysis because of their excellent conductivity and high utilization of active sites. However, traditional substrates, e.g., metal foams and carbon paper, suffer from structural instability and slow mass transfer due to their irregular pore structure, leading to reduced catalytic activity. Herein, we employ selective laser melting technology to construct a three‐dimensional (3D) CuNi self‐supporting electrocatalyst with a microchannel array (CuNi‐P). The ordered and interconnected porous structure efficiently facilitates mass transfer, and the decorated nanoparticles provide additional active sites. The obtained CuNi‐P also exhibits outstanding mechanical properties, ensuring long‐term durability. Moreover, the surface of CuNi‐P exhibits superhydrophilic and superaerophobic properties, enabling efficient mass transfer across the solid‐liquid‐gas three‐phase interfaces. Cu and Ni act synergistically to enhance NO 3 − reduction to ammonia (NH 3 ), delivering the lowest charge‐transfer resistance and a high NH 3 yield rate of 10.6 mg h −1 cm −2 at −0.55 V. Additionally, CuNi‐P exhibits excellent electrocatalytic performance for glycerol oxidation reaction, enabling a bifunctional electrocatalytic system that couples NH 3 and formate production. The system can achieve a high NH 3 Faradaic efficiency of 95.5% at 1.6 V and a current density of 100 mA cm −2 at only 1.4 V, while maintaining stable performance for 500 h.