Salt-induced nanoporous gold electrodes: One-step scalable fabrication of high-performance flexible electrochemical sensors from gold nanoparticles

Here, a simple filtration method for the fabrication of salt-induced nanoporous gold electrodes (SINPGEs) from gold nanoparticles (AuNPs) is reported. This method employs sodium chloride (NaCl) to trigger the aggregation, room-temperature sintering and region-selective deposition of AuNPs on patterned polyvinylidene fluoride (PVDF) membranes during filtration, which enables the one-step scalable fabrication of flexible SINPGEs three-electrode arrays with high conductivity, good mechanical property, large surface area and extremely low cost. Moreover, compared with traditional gold disc electrodes, the nanoporous structure of SINPGEs was demonstrated to apparently improve the electrochemical responses of various electroactive species, e.g., dopamine (DA), uric acid (UA), ascorbic acid (AA) and hydrogen peroxide (H2O2), reflected by the apparent enlargement of redox currents. In addition, the passivation effect of chloride ions (Cl−) on the oxidation of H2O2 at SINPGEs can be greatly repressed by a simple electrochemical activation approach, producing a sensitive H2O2 sensor with a calibration range of 1.0–1000 μM in the presence of 0.1 M Cl−. The present work thus establishes a new approach to the scalable construction of gold electrode-based electrochemical sensors with high performance and low cost.