Piezoelectric ZnO nanoarrays for catalytic detection of H2O2 with ultra sensitivity

Piezo-electrocatalytic semiconductors with the piezoelectric effect and catalytic properties offer unprecedented opportunities in a variety of applications of chemical sensors, electrocatalysts, and photocatalysis. Herein, we demonstrate a flexible piezo-electrocatalytic sensor based on ZnO nanoarrays for ultrasensitive detection of hydrogen peroxide (H2O2), an important substance in many biologic and medical fields. In situ growth of ZnO nanoarrays on flexible gold interdigital electrodes can effectively couple electrical excitation and external strain-induced piezoelectric polarization to promote catalytic reactions. Therefore, the piezo-electrocatalytic sensor measured by chronoamperometry exhibits an unexpectedly high sensitivity of 487 μA mM−1 cm−2, which is superior to previous results. By using finite element analysis, we simulate the piezoelectric effect of ZnO to elucidate the charge transfer between the strained ZnO and H2O2. This work demonstrates a versatile platform of a flexible piezo-electrocatalytic sensor that can use external mechanical energy to improve chemical and biologic detection.