Enhanced electrocatalytic nitrate-to-ammonia conversion performance from Ag-doped Co3O4 nanofibers

Abstract

Conventional ammonia (NH3) production has predominantly relied on the Haber-Bosch process, which poses substantial environmental challenges. Consequently, developing highly efficient electrocatalysts for nitrate (NO3-) reduction is imperative.In this study, silver (Ag)-doped cobalt oxide (Co3O4) nanofibers (NFs) are synthesized via an electrospinning and high-temperature calcination procedure, achieving an enhanced NO3-to-NH3 conversion performance. The resultant optimized 10% Ag-Co3O4 NFs catalyst demonstrates an outstanding Faraday efficiency (FE) of 95.8 ± 0.3% at -0.275 V vs. reversible hydrogen electrode (RHE) and a NH3 yield rate of 29.1 ± 0.3 mg cm-2 h-1 at -0.675 V vs. RHE, markedly surpassing pristine Co3O4 NFs. Furthermore, when employed as the cathode in an assembled aqueous battery, this catalyst achieves a peak power density of 7.2 mW cm-2 and excellent long-term charge-discharge stability. This work presents an innovative strategy for designing advanced electrocatalysts to achieve concurrent NH3 electrosynthesis and power generation, thereby offering a promising avenue for sustainable energy conversion.