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

Abstract

Electrochemical nitrite reduction reaction (NO2−RR) to synthesize NH3 is a green and sustainable technology. Herein, we report porous-rich Pd/CuO nano-olives (Pd/CuO NOs) with heterointerfaces for efficient NO2−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 NO2− and reaction intermediates. Benefiting from structural advantages and interfacial engineering, the Pd/CuO NOs exhibit excellent NO2−RR performance (NH3 yield rate: 906.4 μg h−1 mg−1cat., NH3 Faradaic efficiency: 91.8%, NH3 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 NO2−RR.