Organic-Inorganic Hybrid Films of the Sulfate Dawson Polyoxometalate, [S2W18O62]4-, and Polypyrrole for Iodate Electrocatalysis

Amna Yaqub; Mikhail Vagin; James J Walsh; Fathima Laffir; Indherjith Sakthinathan; Timothy McCormac; Mustansara Yaqub

doi:10.1021/acsomega.2c01287

Organic-Inorganic Hybrid Films of the Sulfate Dawson Polyoxometalate, [S₂W₁₈O₆₂]^4-, and Polypyrrole for Iodate Electrocatalysis

ACS Omega. 2022 Nov 17;7(48):43381-43389. doi: 10.1021/acsomega.2c01287. eCollection 2022 Dec 6.

Authors

Amna Yaqub¹, Mikhail Vagin², James J Walsh^{3

4}, Fathima Laffir⁵, Indherjith Sakthinathan⁶, Timothy McCormac⁶, Mustansara Yaqub⁷

Affiliations

¹ University of Engineering and Technology, G. T. Road, Lahore, Punjab39161, Pakistan.
² Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-601 74Norrköping, Sweden.
³ School of Chemical Sciences, Dublin City University, DCU Glasnevin Campus, Dublin9, Ireland.
⁴ National Centre for Sensor Research, Dublin City University, DCU Glasnevin Campus, Dublin9, Ireland.
⁵ Materials and Surface Science Institute, University of Limerick, LimerickV94 T9PX, Ireland.
⁶ Electrochemistry Research Group, Department of Applied Science, Dundalk Institute of Technology, Dublin Road, DundalkA91 K584, County Louth, Ireland.
⁷ Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS University Islamabad, 1.5 KM Defence Rd, Off Raiwand Road, Lahore, Punjab54000, Pakistan.

Abstract

The Dawson-type sulfate polyoxometalate (POM) [S₂W₁₈O₆₂]^4- has successfully been entrapped in polypyrrole (PPy) films on glassy carbon electrode (GCE) surfaces through pyrrole electropolymerization. Films of varying POM loadings (i.e., thickness) were grown by chronocoulometry. Film-coated electrodes were then characterized using voltammetry, revealing POM surface coverages ranging from 1.9 to 11.7 × 10^-9 mol·cm^-2, and were stable over 100 redox cycles. Typical film morphology and composition were revealed to be porous using atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy, and the effects of this porosity on POM redox activity were probed using AC impedance. The hybrid organic-inorganic films exhibited a good electrocatalytic response toward the reduction of iodate with a sensitivity of 0.769 μA·cm^-2·μM^-1.