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O: Fachverband Oberflächenphysik

O 97: Solid-liquid interfaces: Reactions and electrochemistry III

O 97.5: Vortrag

Freitag, 13. März 2026, 10:45–11:00, TRE/PHYS

Optimizing oxygen vacancies through grain boundary engineering to enhance electrocatalytic nitrogen reduction — •Xiu Zhong¹, Fu Yang², and Yong Lei¹ — ¹Institut für Physik & IMN MacroNano (ZIK), Technische Universität Ilmenau, Ilmenau 98693, Germany — ²School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China

This study develops an efficient N2-reduction catalyst by in-situ anchoring ultrafine MoO2 nanograins on N-doped carbon fibers. Optimized thermal treatment generates abundant grain boundaries that increase oxygen-vacancy concentration, enhance electron transfer, and create highly active N2-trapping sites. The optimal MoO2/C700 catalyst delivers superior performance, achieving an NH3 yield of 173.7 μg h-1 mgcat -1 and a Faradaic efficiency of 27.6% at -0.7 V vs. RHE in 1 M KOH. In-situ XPS and DFT confirm the electronic-structure modulation and strong N2-oxygen-vacancy interaction, revealing electron transfer between adsorbed nitrogen and Mo(IV). Correlating activity with interfacial effects further clarifies the origin of enhancement. The catalyst also shows stable operation for 60 h, demonstrating the promise of grain-boundary engineering to boost oxygen vacancies for efficient and sustainable electrochemical ammonia synthesis.

Keywords: grain boundaries; oxygen vacancy; ammonia synthesis; nitrogen reduction; electrocatalyst