Simple Preparation of Layered Perovskite Ln2cuo4 Nanocrystals with Controllable Phase 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 important hydrogen peroxide. Accordingly, simple sol-gel method plus air calcination at 600 ℃ were carried out herein to synthesize two types of layered perovskite Ln 2 CuO 4 nanocrystals with controllable phase, i.e. T- La 2 CuO 4 and T' -Sm 2 CuO 4 . Then, these nanomaterials were separately modified on bare glassy carbon electrode (GCE) surface by drip coating method, thus assembling efficient non-enzymatic H 2 O 2 electrochemical sensor for the first time. In phosphate buffer solution (pH = 7.0), the La 2 CuO 4 /GCE shows high sensitivity (419.6 mA mM -1 cm -2 ) and low detection limit (160 nM) towards H 2 O 2 , which are significantly superior to those of Sm 2 CuO 4 /GCE. The difference in electrochemical sensing performance is mainly related to their electrode surface areas and conductivities, characteristics of T - and T' -type layered structures, as well as the synergism of interstitial oxygen content and Cu 2+ /Cu + redox coupling. In addition, La 2 CuO 4 /GCE has satisfactory selectivity and stability, and achieves the detection of trace H 2 O 2 in rat serum, contact lens cleaning solution, tap water and disinfectant, indicating that it has certain practical applications in environmental protection and biological analysis