Three-dimensional nanoporous Au films as high-efficiency enzyme-free electrochemical sensors

Herein we develop an enzyme-free electrochemical sensor for hydrogen peroxide (H2O2) and hydrazine (N2H4) by preparing three-dimensional nanoporous gold (NPG) supported on three dimensional Ni foam. The NPG@Ni foam hybrid electrode was prepared via electrodeposition of an AuSn alloy film on a Ni foam substrate, followed by a chemical dealloying process to leach the Sn component. The morphology and structure of the as-prepared NPG@Ni foam hybrid were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectrum (EDS). The as-prepared hybrid electrodes showed high sensitivity and selectivity for the detection of both H2O2 and N2H4. The non-enzymatic sensor exhibits a linear response for H2O2 and N2H4 in the range of 20–9740 and 0.2–110.1μM, with a sensitivity of 2.88 and 10.687mAmM−1cm−2, and a detection limit (S/N=3) of 10μM and 33nM, respectively. The excellent sensitivity and selectivity make the NPG@Ni foam electrodes very attractive for electrochemical sensing applications.