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 exhibits an outstanding Faraday efficiency (FE) of 95.8 ± 5.9% at −0.275 V vs. the 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.