Novel pH microsensor based on a thin film gold electrode modified with lead dioxide nanoparticles

A highly sensitive thin-film pH micro-sensor has been fabricated by deposition of lead dioxide (β-PbO2) nanoparticles (NPs) on a planar gold electrode. The resulting pH microchip electrode displays excellent potentiometric response to pH values with a super-Nernstian slope of 84 mVpH−1 over the pH 0.25–13 range. The NPs were electrochemically placed on the planar gold substrate by low current deposition in combination with high voltage oxidation. The merits offered by this elaborated pH microsensor include fast response time, high sensitivity, reasonable selectivity, simple fabrication, long lifetime and the feasibility of miniaturization and integration.