Preparation of GO film on silver template GO suspension (0.5 mg/mL) was prepared by mixing GO powder (NiSiNa Materials Japan Co., Ltd.) with DI water, followed by 5 hours of ultrasonication and 10 mins of centrifugation with 5000 rpm. The suspension was then used for GO film preparation via vacuum filtration with porous and conductive (1.59 x 10 -8 Ωm) Ag membranes (Sterlitech, 0.2-micron pore size, 25 mm diameter) as substrates. The resulting GO film on AG substrate functions as the working electrode in the electrochemical synthesis.