Heterointerface-triggered electronic structure reformation: Pd/CuO nano-olives motivate nitrite electroreduction to ammonia

Electrochemical nitrite reduction reaction (NO 2 − RR) to synthesize NH 3 is a green and sustainable technology. Herein, we report porous-rich Pd/CuO nano-olives (Pd/CuO NOs) with heterointerfaces for efficient NO 2 − RR. The porous structure of Pd/CuO NOs provides abundant channels for molecular permeation and increases the accessible active sites between the reactant and the catalyst. More importantly, the Pd/CuO heterointerfaces spontaneously establish a built-in electric field in the interfacial region, which favorably adjusts the electronic structure of Pd and Cu sites and optimizes the adsorption of NO 2 − and reaction intermediates. Benefiting from structural advantages and interfacial engineering, the Pd/CuO NOs exhibit excellent NO 2 − RR performance (NH 3 yield rate: 906.4 μg h -1 mg -1 cat. , NH 3 Faradaic efficiency: 91.8%, NH 3 selectivity: 94.9%) at -1.5 V. This work provides a powerful route for fabricating porous-rich heterostructures with local charge polarization and provides a promising strategy for design of efficient catalysts for various electrocatalytic and electrosynthesis applications, beyond NO 2 − RR. The Pd/CuO nano-olives with abundant heterointerfaces and employed as electrocatalysts for NO 2 − reduction reaction (NO 2 − RR) to synthesis ammonia. • Pd/CuO nano-olives were prepared via a two-step synthesis strategy. • The catalysts possess porous-rich structure and abundant Pd/CuO heterointerfaces. • The catalysts exhibit excellent performance for nitrite reduction reaction. • The strategy provides a novel strategy for preparing porous-rich 2D heterostructures.