Synthesis of a Pt/reduced graphene oxide/polydopamine composite material for localized surface plasmon resonance and methanol electrocatalysis

A Pt/rGO/PDA@ITO composite of Pt nanoparticles (NPs), reduced graphene oxide (rGO) and polydopamine (PDA) has been obtained on indium tin oxide glass (ITO). Firstly, a rGO/PDA@ITO composite of rGO and PDA on ITO was formed by immersing ITO into a dopamine solution at room temperature and then a graphene oxide (GO) suspension solution in a water bath at 60 °C for 3 h. Ag NPs were then deposited on the rGO/PDA@ITO surface by immersing rGO/PDA@ITO in an AgNO₃ aqueous solution with the aid of ascorbic acid. Finally, Pt/rGO/PDA@ITO was obtained by immersing Ag/rGO/PDA@ITO in a platinum tetrachloride solution in the presence of ascorbic acid. Localized surface plasmon resonance (LSPR) of the Pt NPs has been found at 260 nm from UV-visible spectra. Cyclic voltammetry curves of Pt/rGO/PDA@ITO and UV absorption peaks of the Pt NPs implied that the sample with the strongest LSPR is the optimal electrocatalyst for methanol oxidation. Cyclic voltammetry of Pt/rGO/PDA@ITO showed that the ratio of current intensity between the forward scan and reverse scan peaks (I_f/I_b) was 1.768, indicating the remarkable anti-poison property of Pt/rGO/PDA@ITO as an electrocatalyst. Its electrochemical active surface area can reach 2.60 m² g⁻¹ at a scan rate of 50 mV s⁻¹. It was found that the current decreased only 38.7% after 200 cycles. The better stability also confirmed the superior tolerance of carbon monoxide and catalytic activity.