What question did this study set out to answer?

This study aims to elucidate how alkali metal cations in electrolytes influence the electrocatalytic performance of cobalt vanadium oxide during the oxygen evolution reaction.

May 21, 2026

Effect of Alkali Metal Ions in Electrolytes on the Electrocatalytic Performance of Cobalt Vanadium Oxide

Key Points

This study aims to elucidate how alkali metal cations in electrolytes influence the electrocatalytic performance of cobalt vanadium oxide during the oxygen evolution reaction.
Fundamental electrochemical studies were performed using Co 3 V 2 O 8 as a model electrocatalyst.
Ex situ techniques like electron microscopy and Raman spectroscopy were employed for analysis.
In situ Raman studies were conducted in 1 M KOH and CsOH to investigate reaction mechanisms.
Exchange current density significantly improved with different alkali metal cations, correlating to reduced overpotential (320 mV).
Cobalt oxyhydroxide species generation was identified in KOH electrolyte along with vanadium dissolution.
In CsOH, distinct V-O bonds were observed, highlighting structural changes in the catalyst under different conditions.

Abstract

The oxygen evolution reaction (OER) is key to the operation of various sustainable technologies like water‐splitting devices and metal‐air batteries. Realization of efficient OER depends on robust electrocatalyst materials as well as optimized electrolytes. The cations in electrolytes have a pronounced impact on the kinetics of OER. However, the mechanistic origin of this effect remains poorly addressed. In this study, using cobalt vanadium oxide Co 3 V 2 O 8 (CVO) as a model electrocatalyst, the cation‐dependent OER activity was investigated using fundamental electrochemical study in conjunction with ex situ (electron microscopy and Raman spectroscopy) analyses. The results demonstrate that OER performance is not only affected by surface/bulk reconstruction, but also governed by electrolyte cation adsorption. In situ Raman study in 1 M KOH electrolyte identified the generation of Co‐oxyhydroxide species accompanied by vanadium dissolution, whereas ex situ Raman spectra revealed a more distinct VO bond in catalysts when subjected to 1 M CsOH. While partial amorphization was noticed in LiOH and NaOH systems, structural retention with irregular Co(O)OH domains was observed in CVO after catalysis in KOH and CsOH electrolytes. Electrochemical evaluation further establishes exchange current density as the sole parameter significantly affected due to the presence of different cations, directly correlating with reduced overpotential (320 mV) and extended durability (>12 hr continuous electrolysis). These findings highlight the critical role of electrolyte cations in modulating the intrinsic kinetics of Co 3 V 2 O 8 toward OER electrocatalysts.

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