Amorphous NiSb2O6-x nanofiber: A d-/p-block Janus electrocatalyst toward efficient NH3 synthesis through boosted N2 adsorption and activation

The electrochemical N-2 reduction reaction (NRR) is greatly challenged by relatively low faradaic efficiency (FE) owing to fierce competition from the H-2 evolution reaction (HER) suffered by the current transition-metal electrocatalysts (d-block elements). Considering the unique electronic structure of group-VA pnictogens (p block elements) that is complementary to d-block elements in HER suppression, we report a conceptually new Janus electrocatalyst to tackle the selectivity challenge. Specifically, an amorphous NiSb2O6-x nanofiber is synthesized, in which Ni and Sb contribute to a synergistic catalysis pathway for inhibiting the two-electron transfer process of HER as well as activating the adsorbed N-2 molecules. Moreover, amorphization is able to produce more oxygen vacancies, thus mimicking the pi back-donation process to promote the NRR performance. Benefiting from this coupled element design and amorphization strategy, the amorphous NiSb2O6-x nanofiber significantly outperforms either component (NiO or Sb2O4) as well as its crystalline counterparts in terms of NH3 yield and FE.

Automated summary

In this study, a novel electrocatalyst was reported to improve the selectivity and efficiency of the N-2 reduction reaction. By coupling element design and amorphization strategy, the amorphous NiSb2O6-x nanofiber showed higher NH3 yield and faradaic efficiency compared to its components and crystalline counterparts.