High-efficiency electrocatalytic nitrate-to-ammonia conversion over CoPd alloy nanoparticles embedded within carbon nanofibers

Electrocatalytic nitrate reduction reaction (NO 3 RR) to ammonia (NH 3 ) provides a promising, environmentally benign, and energy-efficient strategy to eliminate nitrate (NO 3 − ) pollution within the nitrogen cycle while simultaneously producing a valuable chemical feedstock. Herein, we report the synthesis of bimetallic CoPd alloy nanoparticles embedded within carbon nanofibers (CNFs) via a two-step electrospinning and carbonization approach, designed specifically for high-performance NO 3 RR. The interconnected CNFs provide robust structural support, ensuring excellent catalyst stability and cycling performance. Remarkably, the optimized Co 2 Pd 1 -CNF catalyst delivers exceptional NO 3 RR activity, achieving a high NH 3 yield rate of 43.6 ± 0.7 mg h −1  cm −2 at −0.7 V vs. RHE, alongside outstanding long-term stability exceeding 100 h of continuous operation, greatly surpassing not only the single-metallic Co-CNF and Pd-CNF but also most recently reported NO 3 RR electrocatalysts. Moreover, the integration of Co 2 Pd 1 -CNFs as the cathode into an aqueous Zn-NO 3 − battery demonstrates its practical utility, yielding an impressive power density of 9.28 mW cm −2 . This work highlights CoPd-CNFs as a highly efficient and durable catalyst for sustainable NO 3 − removal, simultaneously enabling valuable ammonia synthesis and demonstrating promising applicability in next-generation energy storage devices.