Electrochemical determination of folic acid using carbon/ZnO nanowire arrays/graphene foam

Three-dimensional (3D) graphene foam (GF) was synthesized by chemical vapor deposition (CVD). Following this, ZnO nanowire arrays (ZnO NWAs) were grown on the 3D GF by hydrothermal synthesis. Finally, carbon (C) was deposited on the surface of ZnO NWAs by CVD to obtain a C/ZnO NWAs/GF hybrid. This composite was used to detect the presence of folic acid. The experimental results show that the GF inherits the 3D macroporous structure of nickel foam and that the ZnO NWAs are uniformly and vertically grown on the 3D GF. The length and diameter of the ZnO nanowires are~50 nm and 2 μm, respectively. Carbon is deposited on the surface of ZnO NWAs, and the C/ZnO NWAs/GF is used as a working electrode to detect folic acid (FA) using an electrochemical method. The experimental results show that the sensitivity of the electrode for FA is 0.13 μA·μmol^-1·L and it has good selectivity for detecting FA in the presence of uric acid. The electrode also has excellent reproducibility and stability.