Non-enzymatic photoelectrochemical sensing of hydrogen peroxide using hierarchically structured zinc oxide hybridized with graphite-like carbon nitride

Hierarchically structured ZnO hybridized with graphitic carbon nitride (g-C3N4) is introduced as a new material for non-enzymatic photoelectrochemical sensing of hydrogen peroxide (H2O2). It is based on the measurement of the decrease in the photocurrent produced by H2O2 which consumes the photoinduced electrons ejected by the ZnO/g-C3N4 composite. The g-C3N4 has a beneficial effect in extending the band width of light absorption of ZnO into the visible region and to promote the separation of the photoinduced carriers. This results in an enhanced photocurrent and high-sensitivity. The ZnO/g-C3N4 composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectrometry, and UV-vis spectrophotometry. Under the optimized condition, the sensor has a linear response to hydrogen peroxide in the 1.3-79.8 nM concentration range, and the detection limit is 0.38 nM. The sensor is sensitive, selective, stable and can be fabricated at low costs.