Synergistic Electronic Modulation on Pd−Ag Heterostructures to Unlock C−N Coupling for Efficient Urea Electrosynthesis

Abstract Direct electrosynthesis of urea via coupling NO3− and CO2 represents an effective strategy to supersede the high-energy-consuming Bosch−Meiser process. However, this process involves the synergistic activation of NO3− and CO2 and the crucial coupling of C−N intermediates, and it still poses an enormous challenge. Herein, a p-PdNs-Ag heterojunction catalyst was synthesized via a wet-chemical method to enable the efficient electrosynthesis of urea from CO2 and NO3− coupling. By synergistically integrating the distinct merits of both metals, we synthesized a hybrid catalyst wherein the strained porous Pd architecture not only serves as a high-surface-area matrix for anchoring Ag nanoparticles but also profoundly alters the local electronic environment of the Ag moieties. Specifically, the Pd scaffold functions to provide dense active sites, enhance mass transport of reactants, and enrich key intermediates for nitrate reduction, with the Ag domains concurrently favoring the conversion of CO2. The optimized p-PdNs-Ag catalyst achieved a high urea yield rate of 64.18 mmol gcat−1 h−1 and a Faradaic efficiency of 20.81% and also exhibited excellent cycling stability. This work provides new insights into the design of efficient C−N coupling electrocatalysts from the perspectives of electronic modulation and synergistic dual-active sites.