ABSTRACT
Sandwich polyoxometalate [WCo3(H2O)2(CoW9O34)2]12- (Co-WCo3) heterogenized with poly(vinyl butyl imidazolium) cations (PVIM+) acts as a stable electrochemical water oxidation catalyst in 1 M KOH with 0.28 V@10 mA cm-2 overpotential and TOF of 6.16 s-1. Various in situ spectroelectrochemical studies and control experiments provide the details of the catalytic activities and long-term stability of the catalyst.
ABSTRACT
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.
