CoV₂O₆–V₂O₅ Coupled with Porous N-Doped Reduced Graphene Oxide Composite as a Highly Efficient Electrocatalyst for Oxygen Evolution

Abstract

Electrocatalysts with high intrinsic activity for the oxygen evolution reaction (OER) are greatly desired for sustainable oxygen-based electrochemical energy conversion. In this work, the bimetallic oxide composite consisting of CoV2O6 and V2O5 anchoring on nitrogen-doped reduced graphene oxide (CoV2O6–V2O5/NRGO-1) was synthesized directly by carbonization of the polyoxometalates, ethylenediamine, and graphene oxide precursors. CoV2O6–V2O5/NRGO-1 used as an electrocatalyst exhibits an ultralow overpotential of 239 mV vs RHE at the current density of 10 mA cm–2 and excellent stability in 1 M KOH. Surprisingly, it has high intrinsic activity with the turnover frequency of 1.80 s–1 at the overpotential of 300 mV, which is the highest among the electrocatalysts reported to date. Theoretical calculation proves that the outstanding electrocatalytic performance is attributed to synergistic effects, in which CoV2O6 acts as active sites while the hydrogen bond between V2O5 and intermediate HOO* of the OER greatly decreases the composite adsorption energy, thus reducing the overpotential. Most importantly, the results demonstrate for the first time that intermolecular hydrogen bonding plays a key role in improving electrocatalytic properties for the OER, which reveals a new method of designing novel OER electrocatalysts.

A 2D NiFe Bimetallic Metal–Organic Frameworks for Efficient Oxygen Evolution Electrocatalysis

“…The results also reveal that although the Ni‐based MOFs exhibit better OER activity in potentials, the Fe could help to improve the kinetics, which is important for catalytic process. The electrochemical impedance spectra (EIS) measurements were carried out to evaluate the charge transfer efficiency (Figure c) . The resistance is obvious decreased when a small amount of Fe is introduced; however, as the Fe is further increased, the charge transfer efficiency decline, which maybe resulted from collapse of structure.…”

Cobalt-vanadium bimetal-based nanoplates for efficient overall water splitting

“…The good conductivity and stability of VN are also favorable for its application either as catalyst or as support. It is shown that the combination of oxides with V and Co can result in OER active catalysts [40][41][42]. Also, the effective combination of early and late TMs is useful for designing the advanced materials [43][44][45].…”

POM & MOF‐based Electrocatalysts for Energy‐related Reactions

“…This work was the first evidence of bimetallic carbide with high OER activity.B esides this, also ab imetallic oxide composite consisted of CoV 2 O 6 and V 2 O 5 anchoring on nitrogen doped reduced graphene oxide (CoV 2 O 6 -V 2 O 5 /NRGO) was prepared through carbonization of ap olyoxovanadate in the presenceo fe thylenediamine, whicha cted as nitrogen source and reductive agent for GO, while rGO served as conductive base. [131] The electrocatalyst exhibited al ow overpotential of h 10 = 0.239 Vv s. RHE and exceptional stability.I ts intrinsic activity (TOF = 1.80 s À1 at h = 0.300 V) is among the largestr eported to date. The resultsd emonstrated that CoV 2 O 6 acted as active site, while the hydrogen bond between V 2 O 5 and HOO*O ER intermediate decreased the composite adsorption energy and thus the overpotential.…”