Stabilization of Cobalt-Polyoxometalate over Poly(ionic liquid) Composites for Efficient Electrocatalytic Water Oxidation

Adhikary, Subhasis D.; Tiwari, Aarti; Nagaiah, Tharamani C.; Mandal, Debaprasad

Stabilization of Cobalt-Polyoxometalate over Poly(ionic liquid) Composites for Efficient Electrocatalytic Water Oxidation

2018

Adhikary, Subhasis D. | Tiwari, Aarti | Nagaiah, Tharamani C. | Mandal, Debaprasad

The key to unlock a renewable, clean, and energy-dense hydrogen fuel lies in designing an efficient oxygen evolving catalyst exhibiting high activity, stability, and cost-effectiveness. This report addresses an improved activity toward oxygen evolution by a composite of cobalt-polyoxometalate [Co₄(H₂O)₂(PW₉O₃₄)₂]¹⁰– (CoPOM) and an ionic polymer, poly(vinyl butyl imidazolium) (PVIM), in highly alkaline media. PVIM provides a stable platform for CoPOM and acts as a conductive linker between CoPOM and the electrode surface, forming a concrete solid composite, which balances the multinegative charge of CoPOM synergistically. This improved stability and conductivity of CoPOM by PVIM in the PVIM–CoPOM composite performs remarkable electrocatalytic water oxidation with a very low overpotential of 0.20 V and a very high current density of 250 mA/cm² (at 1.75 V vs RHE) with a turnover frequency (TOF) of 52.8 s–¹ in 1 M NaOH.

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