Sensing mechanism of RuO2–SnO2 thick film pH sensors studied by potentiometric method and electrochemical impedance spectroscopy

Flexible potentiometric pH sensors for wearable systems

“…176,177 Some of the approaches reported to stabilize the potential of REs include a lead-free glass-KCl composite layer printed on the top of an Ag/AgCl lm. 167,178,179 The decay of the glass-KCl composite electrode in solution is very low and hence the fabricated thick lm REs can show lifetime of over 2 years. 179,180 The exible REs developed with this composite material can also exhibit excellent performance (Fig.…”

“…167,178,179 The decay of the glass-KCl composite electrode in solution is very low and hence the fabricated thick lm REs can show lifetime of over 2 years. 179,180 The exible REs developed with this composite material can also exhibit excellent performance (Fig. 3b), 180 with negligible variation in potential (AE4 mV) under different bending states (radius 3, 5, and 7 mm).…”

“…For instance, more than 6 months of continuous water monitoring has been demonstrated using an array of RuO 2 based pH sensing electrodes (sensitivity 55.64 mV pH À1 ). 179,217 However, the lack of exibility and cost of the electrode are some of the bottlenecks associated with this sensor design. The cost of the sensing array may be overcome by combining RuO 2 with inert oxide based binary electrodes.…”

“…The cost of the sensing array may be overcome by combining RuO 2 with inert oxide based binary electrodes. 37,167,179,218 For example, a low-cost potentiometric sensing array fabricated by screen printing a composite ink consisting of graphene platelets and submicron RuO 2 powders has been reported. 219 This approach also addresses the issues related to exibility.…”

RuO2 pH Sensor with Super-Glue-Inspired Reference Electrode

“…The use of RuO 2 films for the manufacture of solid state potentiometric pH sensors has several advantages, namely Nernstian pH sensitivity, insolubility over a wide pH range, good reproducibility, low hysteresis, and reduced cost (in comparison to the more commonly studied IrO 2 films) [ 1 , 2 , 3 , 4 ]. The pH sensing properties of RuO 2 films have been reported by numerous groups [ 5 , 6 , 7 ]. Briefly, RuO 2 undergoes the following redox reaction: where the electrode’s potential, E , in mV and at 22 °C, is given by the Nernst equation, which simplifies to: …”