Further enhancement of the light-regulated mixed-potential signal with ZnO-based electrodes

Abstract

Abstract UV illumination has been confirmed to be essentially increased the response magnitude of potentiometric gas sensors. Nevertheless, the detection limit of the sensor is still inadequate for real application even upon UV light, whilst, how to efficiently enhance the light-regulated mixed-potential signal is still unclear. In this research, the strategy of using the more photoactive ZnO-based composite as the sensing-electrode (SE) for potentially further enhancing the sensing value is proposed and confirmed. Typically, in comparison with ZnO-SE, ZnO-based composite SE is beneficial for further promoting the light-regulation effect. Particularly, when upon illumination, the detection limit of the sensor consisting of the composite electrode (towards benzene) reaches 0.109 ppm, while that of the value for the sensor using ZnO-SE is 0.898 ppm. The promoting mechanism is clarified from the perspective of the electrocatalytic activity & gas-phase reactivity. In summary, forming the ZnO-based composites makes them ideal for generating abundant e − a nd h + when upon illumination, leading to the obvious increase in the catalytic activity of both cathodic & anodic reaction and thereby further raised the mixed-potential signal. Conclusively, this proof-of-concept opens a brighter future for designing future high-performance potentiometric gas sensors.