One-Pot Synthesis of Ce-Based Nanocomposites for Fluorescence and Colorimetric Dual-Mode Sensing Platform...

Ce-based nanomaterials have been widely studied as catalyst for their unique electronic structure, but there are few reports on the combination of cerium catalytic activity and photoluminescence performance. In this paper, by adjusting the molar ratio of Ce/P, CeO₂/CePO₄ nanocrystal were synthesized in one-step, which integrated the enzyme activities of CeO₂ and CePO₄, as well as the optical property of CePO₄ together. Taking H₂O₂ as analyte model, utilizing the catalase oxidization activity of CeO₂/CePO₄, TMB molecule can be oxidized, leading to the increased absorption intensity of 652 nm, realizing the colorimetric assay of H₂O₂. On the other hand, using the fluorescence of CeO₂/CePO₄ at 338 nm as output signal, which can be quenched by H₂O₂ since Ce³⁺ ions were oxidized into Ce⁴⁺, realizing H₂O₂ fluorescence detection. Compared with the single-signal probe, CeO₂/CePO₄ provides two sensing modes of fluorescence and colorimetry for H₂O₂ discrimination to obtain different test results, which can be mutually verified and effectively improve the detection accuracy.