Lacunary Polyoxometalate iImmobilized on Graphene Oxide: An Effective Electrocatalyst for Hydrogen Generation in Aqueous Solution

Abstract A new stable nanocomposite comprising thiol‐functionalized lacunary Keggin‐type phosphomolybdate (PMo₁₁) and graphene oxide (GO) was prepared via the thiol‐ene click reaction. Various characterization techniques, like FT‐IR spectroscopy, energy‐dispersive X‐ray (EDX) spectroscopy, and X‐ray diffraction (XRD) analysis showed the strong covalent interaction of GO and PMo₁₁ species and successful formation of PMo₁₁−S−GO nanocomposite. Nitrogen adsorption‐desorption analysis revealed the decrease in GO surface area after introducing PMo₁₁ species. The prepared nanocomposite was employed in the electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H₂SO₄ solution. A low overpotential of 335 mV and small Tafel slope of 71 mV.dec⁻¹ were obtained in electrocatalytic HER experiments. The nanocomposite exhibited high stability and negligible loss of electrocatalytic activity for at least 850 cycles which is a result of the stable covalent attachment of lacunary Keggin type phosphomolybdate to the surface of GO nanosheets.