T- and T′-type layered perovskite Ln2CuO4 nanocrystals for enhanced sensing detection of hydrogen peroxide

Nanostructured rare earth cuprates have recently attracted extensive attention as a promising non-noble metal electrocatalyst. However, they are rarely used to construct electrochemical sensors, even no report on hydrogen peroxide detection. Accordingly, two types of layered perovskite Ln2CuO4 nanocrystals with different structures, i.e., T-La2CuO4 and T′-Sm2CuO4 were synthesized from sol-gel method followed by calcining at 600 ℃ in air. Then, these nanomaterials were separately modified on the surface of bare glassy carbon electrode (GCE) by drop coating method, thus assembling efficient non-enzymatic H2O2 electrochemical sensor for the first time. In phosphate buffer solution (pH = 7.0), the La2CuO4/GCE shows high sensitivity (419.6 μA mM−1 cm−2) and low detection limit (160 nM) towards H2O2, which are significantly superior to those of Sm2CuO4/GCE. The difference in electrochemical sensing performance is mainly related to their electrode surface area and conductivity, characteristics of T- and T′-type layered structures, as well as the synergism of interstitial oxygen content and Cu2+/Cu+ redox coupling. In addition, La2CuO4/GCE has satisfactory selectivity and stability, and achieves the detection of trace H2O2 in rat serum, contact lens cleaning solution, tap water and disinfectant, indicating that it has certain practical applications in environmental protection and biological analysis.