Location effects of vanadium in NiFe layered double hydroxides for oxygen evolution reaction

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-09, Vol.12 (35), p.23447-23453
• Main Authors: Ma, Mengze, Zhang, Yechi, Ding, Xiaoqian, Jing, Jianlei, Jin, Linbo, Liu, Wei, Zhou, Daojin, Sun, Xiaoming
• Format: Article
• Language: English
• Subjects: Catalysts; Electrocatalysts; Electrochemistry; Electrolytes; Hydroxides; Inductively coupled plasma; Interlayers; Intermetallic compounds; Iron compounds; Laminates; Nickel compounds; Oxygen evolution reactions; Potassium hydroxides; Vanadium
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d4ta03436h

NiFe layered double hydroxides (NiFe-LDHs) have been widely acknowledged as a promising anode electrocatalyst in alkaline oxygen evolution reactions (OERs), and vanadium has demonstrated its capability to improve their OER performance. Considering that V can exist as three vanadium-based species, i.e. , doped V III in LDH laminates, intercalated VO 3 − between LDH interlayers, and free VO 3 − as an additive in KOH electrolyte, we systematically studied and compared their effects in determining the OER performance of NiFe-LDHs. Electrochemical results reveal that all three conditions mentioned above individually can improve the OER performance of NiFe-LDHs. When two of these conditions are present at the same time, the combination of VO 3 − intercalated into LDHs as the catalyst and free VO 3 − as the additive in KOH electrolyte shows the best OER performance, even exceeding the performance exhibited by the combination of all three conditions. Ex situ Raman results indicate that VO 3 − intercalation triggers an active γ-phase formation of NiFe-LDHs; in situ Raman data further reveal that VO 3 − as an electrolyte additive stabilizes this active phase and slows down the dissolution of LDHs, as supported by inductively coupled plasma characterization. V can exist as three vanadium-based species, i.e. , doped V III in LDHs laminates, intercalated VO 3 − between LDHs interlayers, and free VO 3 − as an additive in KOH electrolyte. The study shows their role in altering the OER performance of NiFe-LDHs.