Ni-doped spinel zinc ferrite for H2O2 detection: Enhancing H2O2 performance through valence state modulation to promote Fenton reaction

Electrochemical sensors for nonenzymatic hydrogen peroxide (H2O2) detection have gained more attentions due to their high sensitivity, practicality, simplicity and low-cost in the application of biological, food and environmental fields. The electrode materials are extremely important for enhancing the accuracy and sensitivity for nonenzymatic H2O2 sensors. Herein, the spinel zinc ferrite (ZnFe2O4) by nickel (Ni) doping was synthesized to promote the accuracy and sensitivity for H2O2 detection in this work. The results present that the atomic ratio of Fe2+/Fe3+ in ZnFe2O4 is increased after Ni doping and the highest Fe2+/Fe3+ atomic ratio reaches to 3.22 for Zn0.7Ni0.3Fe2O4. Due to the good catalytic activity of ferrous ion with H2O2, the synthesized Zn0.7Ni0.3Fe2O4/GCE exhibits extraordinary catalytic performance on H2O2 detection. The linear range is widely from 20 μM to 10 mM with a detection limit of 5 μM, and a high sensitivity of 3.8817 μA mM−1 cm−2. In addition, the Zn0.7Ni0.3Fe2O4/GCE also shows good reproducibility, repeatability, stability, interference resistance and reliable detection in real environmental detection for H2O2. Thus, the modulation of valence state for spinel oxides in H2O2 detection is a promising and facile method on the development of effective nonenzymatic H2O2 sensors.