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.