Electrochemical nitrate reduction reaction (NO3RR) to ammonia (NH3) represents a sustainable route for both wastewater purification and value-added chemical product. However, developing industrially viable catalysts that combine high efficiency and robust durability remains a challenge. Here, we engineer a series of Mn-doped Co3O4 catalysts with controlled Mn contents via a metal–organic framework (MOF)-derived approach. A distinct volcano-type relationship is observed between the Mn doping level and the NO3RR performance, where optimal Mn15–Co3O4 achieves a remarkable nitrate (NO3–) conversion of 95.48%, 99.19% selectivity and 96.71% Faradaic efficiency toward NH3. More importantly, we unveil that this activity trend is synchronously mirrored by the evolution of three key descriptors: the electrochemically active surface area, the Co2+/Co3+ ratio, and the concentration of oxygen vacancies, all peaking at the same optimal doping level. This correlation establishes a robust structure–activity relationship, demonstrating that moderate Mn doping maximally synergizes morphological advantages and electronic modulation. This work offers an intriguing pathway for the application of MOF-derived materials and provides valuable insights for the rational design of efficient electrocatalysts.
Xu et al. (Wed,) studied this question.