Amperometric sensing of hydrogen peroxide via highly roughened macroporous Gold-/Platinum nanoparticles electrode

A macroporous Au electrode with a very rough surface arising from electroplated Pt nanoparticles (macroporous Au-/nPts) was newly developed and characterized for its suitability for hydrogen peroxide (H2O2) sensing applications. The surface morphology and composition of the macroporous Au-/nPts were measured by the use of scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. Then, the surface roughness and electro-catalytic characteristics were analyzed through the electrochemical analysis method. The porosity and window-pore size of the macroporous Au electrode were approximately 50% and 100–300 nm, respectively. The sizes of the Pt nanoparticles ranged from 5 nm to 10 nm. The roughness factors (RFs) of macroporous Au and Au-/nPts electrodes were measured and calculated by the use of cyclic voltammograms in 1 M sulfuric acid, and found to be 88.6 and 488, respectively. The fabricated macroporous Au and macroporous Au-/nPts electrodes were also characterized and compared in a 0.1 M phosphate buffer saline (PBS, pH 7.4) solution with various H2O2 concentrations. The macroporous Au-/nPts electrode showed a very much higher sensitivity of 264 μA mM−1 cm−2 to H2O2 compared with the macroporous Au electrode (110 μA mM−1 cm−2). Furthermore it was not affected by interfering species like ascorbic acid (AA) and acetaminophen (AP). Also, the macroporous Au-/nPts exhibited an extremely low working potential of 0.1 V, detection limit of 50 μM, and fast response time within 10–20 s.