image: The (FeCoNiCu)Ox electrocatalyst was first prepared using the rapid Joule-heating method within a short duration at the temperature of 1100 K. XRD results suggest that the (FeCoNiCu)Ox electrocatalyst exhibits a characteristic pattern consistent with NiFe2O4 (PDF#10-0325), confirming its typical spinel structure. TEM image displays that the (FeCoNiCu)Ox electrocatalyst consists of many nanoparticles in tens of nanometers in diameter. The STEM and EDS elemental mapping images verify the homogeneous distribution of Fe, Co, Ni, Cu and O elements in the nanoparticles. The HR-TEM image of the (FeCoNiCu)Ox electrocatalyst mainly indexed to NiFe2O4 (311) and (400), which is in good agreement with the XRD results.
Credit: ©Science China Press
Recently, Professor Zhe Weng and Chunpeng Yang from Tianjin University published a paper entitled "Unveiling multi-element synergy in polymetallic oxides for efficient nitrate reduction to ammonia". In this study, the (FeCoNiCu)Ox/CeO2 electrocatalyst for the reduction of NO3− to NH3 was prepared using the rapid Joule-heating method within a short duration. Electrochemical measurements revealed that the (FeCoNiCu)Ox/CeO2 electrocatalyst exhibited a high Faradaic efficiency for NH3 exceeding 90% in the potential range of 0 to −0.4 V vs. RHE, along with a high NH3 yield rate of 30.3 mg h−1 cm−2. Moreover, the (FeCoNiCu)Ox/CeO2 electrocatalyst demonstrated excellent long-term stability for more than 10 h at 200 mA cm−2.
Through a series of comprehensive experiments, the individual contributions of each element and their synergistic effect have been clearly elucidate. Specifically, the Cu active sites efficiently reduce NO3− to nitrite (NO2−) at low overpotential, while the adjacent Co sites facilitate the deep reduction of intermediate NO2−. The Fe and Ni sites play a crucial role in promoting water dissociation to ensure sufficient proton supply. Simultaneously, the CeO2 component increases the active surface area of the (FeCoNiCu)Ox electrocatalyst and improves the NH3 yield rate, making it suitable for industrial applications. This work offers significant insights for the design of highly efficient multi-element electrocatalysts.
See the article:
Unveiling multi-element synergy in polymetallic oxides for efficient nitrate reduction to ammonia
https://www.sciengine.com/SCMs/doi/10.1007/s40843-024-3017-4
Journal
Science China Materials