Hexachloroplatinic(IV)-GO colloids as ideal electrodes modification materials for electrochemical sensing, HER and OER

In this study, a versatile electrode modification material [PtCl6]2--GO colloid was prepared by adsorption of Hexachloroplatinic(IV) ([PtCl6]2-) onto protonated GO (pH = 2). Two modification strategies, namely surface drop coating and in situ electrochemical deposition, were employed to grow [PtCl6]2--GO in situ as Pt-rGO on the surfaces of screen-printed carbon electrode (SPCE), copper foam (CuF), and nickel foam (NiF). The Pt-rGO obtained by this gentle method features extremely small Pt particle sizes (1.4 nm). The benefits of the prepared modification material and electrode modification strategies were confirmed through Furantoin (NF) electrochemical sensing, HER, and OER. The results indicated that SPCE modified with 1 wt% Pt-rGO achieved a very low NF detection limit of 0.82 nM (S/N = 3, DPV) and a wide detection range of 0.1–1650 μM (i-t). Additionally, for HER activity, a low overpotential of 34.6 mV was achieved from Pt-rGO/NiF at pH = 14 and the overpotential of 68.72 mV was achieved from Pt-rGO/CuF at pH = 0.14. For OER activity, an acceptable overpotential of 370.9 mV was achieved from Pt-rGO/NiF at pH = 14. Finally, the electrocatalytic mechanism of Pt-rGO was studied using Kelvin probe force microscopy (KPFM), and the hypothesis of a potential electrocatalytic activity center in the rGO fold/edge region was proposed.